Followup to r1220740, fix a FAIL caused by libmagic not treating as text a file containing a single alphanumeric character.
Followup to r1220740, fix a FAIL caused by libmagic not treating as text
a file containing a single alphanumeric character.

* subversion/tests/cmdline/log_tests.py
  (guarantee_repos_and_wc): Put more than a single character in new file.
  (log_diff): Expect new content.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1220861 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion