Fixes the following errors in 'make distcheck':

1)
  GEN      libnm/fake-typelib/NMClient.typelib
 failed to open 'libnm/fake-typelib/NMClient.typelib.tmp': No such file or directory
 make[2]: *** [libnm/fake-typelib/NMClient.typelib] Error 1

2)
  GEN      libnm/fake-typelib/typelibs.c
 ../../libnm/fake-typelib/typelibs.gresource.xml: Failed to locate “NetworkManager.typelib” in any source directory.
 make[1]: *** [Makefile:17790: libnm/fake-typelib/typelibs.c] Error 1

3)
 ERROR: files left in build directory after distclean:
 ./libnm/fake-typelib/typelibs.c
 ./libnm/fake-typelib/NMClient.typelib
 ./libnm/fake-typelib/NetworkManager.typelib

Fixes: 4d1f090a