cppCheck: Suspicious condition.

AFAIK, there is no actual problem with the existing code.  'rv' would only not have the 'expected' value, but the execution
path would remain the same.
However, the patched code is more logical. We put the returned value in 'rv', then test it against 0.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1407853 13f79535-47bb-0310-9956-ffa450edef68