libxml-2.0: add xmlSearchNs and xmlSearchNsByHref
libxml-2.0: add xmlSearchNs and xmlSearchNsByHref

Fixes bug 692061.

frida/vala,flobrosch/vala-fixes,Distrotech/vala,frida/vala,frida/vala,spidermonkdust/vala,GNOME/vala,xdave/pvala,playya/vala,flobrosch/vala-fixes,flobrosch/vala-fixes,rvu95/vala,spidermonkdust/vala,GNOME/vala,Distrotech/vala,frida/vala,playya/vala,Distrotech/vala,GNOME/vala,frida/vala,rvu95/vala,GNOME/vala,spidermonkdust/vala,playya/vala,rvu95/vala