clone: plug a miniscule leak

The remote_name variable is first assigned a copy of the value of
the "clone.defaultremotename" configuration variable and then by the
value of the "--origin" command line option.  The former is prepared
to see multiple instances of the configuration variable by freeing
the current value of the variable before a copy of the newly
discovered value gets assigned to it.  The latter however blindly
assigned a copy of the new value to the variable, thereby leaking
the value read from the configuration variable.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/clone.c

diff --git a/builtin/clone.c b/builtin/clone.c
index 5231656..194d50f 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -1106,8 +1106,10 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	 * apply the remote name provided by --origin only after this second
 	 * call to git_config, to ensure it overrides all config-based values.
 	 */
-	if (option_origin != NULL)
+	if (option_origin != NULL) {
+		free(remote_name);
 		remote_name = xstrdup(option_origin);
+	}
 
 	if (remote_name == NULL)
 		remote_name = xstrdup("origin");