Patch from Scott McKellar:

Patch from Scott McKellar:

1. The functions _rest_xml_output and _escape_xml are now static, and
a couple of their parameters are now const.

2. In json_string_to_xml() we were leaking res_xml in the case of an
early return.  I moved the early return out of the way.

3. In _rest_xml_output() we were leaking tag in the case of an early
return.  I plugged that leak.

4. In a couple of spots I replaced buffer_data() with buffer_release(),
and eliminated two intermediate variables that are no longer needed.

git-svn-id: svn://svn.open-ils.org/ILS/trunk@8953 dcc99617-32d9-48b4-a31d-7c20da2025e4