1. Test Instr before dereference it in http_RecvPostMessage.
(Though it never becomes NULL because NULL is not passed to
the static method)
2. Avoid strdup(NULL) in ixmlElement_setAttributeNS.
Those are detected by llvm scan-build.
(cherry picked from commit a383cbb8e20545222880f064a5b27c15abbf9280)
77559473c1