Try to simplify sensitive config value for user

We now always put the "pl:" prefix for plain text to make it obvious
in the Dashboard that we actually did something. The explanation text
has also been improved.
diff --git a/resources/com/google/enterprise/adaptor/resources/index.html b/resources/com/google/enterprise/adaptor/resources/index.html
index 0a6af83..70306ae 100755
--- a/resources/com/google/enterprise/adaptor/resources/index.html
+++ b/resources/com/google/enterprise/adaptor/resources/index.html
@@ -88,18 +88,18 @@
   <h2>Adaptor Configuration</h2>
   <table id="gaf-config-table"></table>
 
-  <h2>Sensitive Value Encoding</h2>
-  <p>Passwords and other security-sensitive configuration values are not saved
-    as simple plain-text in the configuration. Instead, they are encoded using
-    one of three methods.
-    <li><strong>Plain text</strong> allows the password or other information to
-      be read by anybody who can read the configuration.
-    <li><strong> Obfuscated</strong> encodes the information in a highly
-      unreadable format, but it is possible for anyone to retrieve the original
-      text.
-    <li><strong>Encrypted</strong> uses your HTTPS encryption key to encrypt the
-      value. An encrypted value is tied to the encryption key, so it cannot be
-      copied between Adaptors.</p>
+  <h2>Storing Sensitive Values</h2>
+  <p>Passwords and other security-sensitive configuration values can be
+    specified in configuration as <code>prefix:data</code>, where the prefix
+    specifies how the value is stored. The value can be stored as:
+    <li><strong>Plain text</strong> allowing the password or other information
+      to be read by anybody who can read the configuration. Denoted by "pl"
+      prefix.
+    <li><strong>Obfuscated</strong> where the information in a highly unreadable
+      format, but it is possible for anyone to retrieve the original text.
+      Denoted by "obf" prefix.
+    <li><strong>Encrypted</strong> which uses your HTTPS encryption key to
+      encrypt the value. Denoted by "pkc" prefix.</p>
   <p><form id="gaf-sec-form">
     Sensitive Value: <input type="password" name="secvalue" id="#gaf-sec-value">
     <br>
diff --git a/src/com/google/enterprise/adaptor/SensitiveValueCodec.java b/src/com/google/enterprise/adaptor/SensitiveValueCodec.java
index 99d8440..a228eb0 100644
--- a/src/com/google/enterprise/adaptor/SensitiveValueCodec.java
+++ b/src/com/google/enterprise/adaptor/SensitiveValueCodec.java
@@ -84,14 +84,11 @@
     String encoded;
     switch (security) {
       case PLAIN_TEXT:
+        // We always apply the prefix, even if it isn't strictly necessary. This
+        // is to make it obvious that the process actually did something to the
+        // user and makes them more aware of the pl: prefix if they need to use
+        // it.
         encoded = readable;
-        if (!encoded.contains(":")) {
-          // If the string contains something that may be a prefix, then we want
-          // to go through the normal process of adding a the prefix. Otherwise,
-          // there should be little chance it will be mis-interpreted and the
-          // user gets to use a simplier format.
-          return encoded;
-        }
         break;
 
       case OBFUSCATED:
diff --git a/test/com/google/enterprise/adaptor/SensitiveValueCodecTest.java b/test/com/google/enterprise/adaptor/SensitiveValueCodecTest.java
index 0e63015..c57d36f 100644
--- a/test/com/google/enterprise/adaptor/SensitiveValueCodecTest.java
+++ b/test/com/google/enterprise/adaptor/SensitiveValueCodecTest.java
@@ -74,11 +74,7 @@
     final String golden = "";
     for (SecurityLevel security : SecurityLevel.values()) {
       String encoded = codec.encodeValue(golden, security);
-      if (security == SecurityLevel.PLAIN_TEXT) {
-        assertEquals(golden, encoded);
-      } else {
-        assertFalse(golden.equals(encoded));
-      }
+      assertFalse(golden.equals(encoded));
       assertEquals(golden, codec.decodeValue(encoded));
     }
   }