Fix issue 1692: obscure bugs in formatting of time/date strings.
Fix issue 1692: obscure bugs in formatting of time/date strings.

* subversion/libsvn_subr/time.c (svn_time_to_human_cstring): 
  Fix the formatting of negative fractional-hour time offsets: an offset
    of -75 minutes was written as "-01-15" instead of the correct "-0115".
  Ensure that the string is terminated even if the human-readable part
    cannot be written.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@848755 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion