Merge branch 'pw/p4-various-fixes'

* pw/p4-various-fixes:
  git p4: remove unneeded cmd initialization
  git p4: fix labelDetails typo in exception
  git p4 test: display unresolvable host error
  git p4: catch p4 errors when streaming file contents
  git p4: handle servers without move support
  git p4: catch p4 describe errors