Fix the rpath removal
    
    As noted in commit a90bc2e7, editing libtool to prevent rpaths breaks
    the introspection compiler as it needs the rpaths during build to find
    libs that are in build directories. Normally libtool relinks the libs
    during 'make install', but this doesn't work for Fedora's lib64.
    
    As a fix, kill the unwanted rpaths in %install with chrpath -- this will
    run after the build has finished, and won't interfere with the
    introspection compiler.