Merge branch 'pw/git-p4'

Various "git p4" updates.

* pw/git-p4:
  git p4 doc: use two-line style for options with multiple spellings
  git p4 test: examine behavior with locked (+l) files
  git p4: fix an error message when "p4 where" fails
  git p4: handle files with wildcards when doing RCS scrubbing
  git p4 test: do not pollute /tmp
  git p4 test: run as user "author"
  git p4 test: is_cli_file_writeable succeeds
  git p4 test: explicitly check p4 wildcard delete
  git p4: work around p4 bug that causes empty symlinks
  git p4 test: ensure p4 symlink parsing works
  git p4 test: wildcards are supported