Fix issue #2090.  Fix out-of-bounds error which lead to sending non-XML-safe properties unencoded over DAV.
Fix issue #2090.  Fix out-of-bounds error which lead to sending non-XML-safe
properties unencoded over DAV.

* libsvn_subr/xml.c (svn_xml_is_xml_safe): When accessing the array,
  cast the char to an unsigned char, instead of an int, so that negative
  char values don't get interpreted as negative ints.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion