fix inverted return value check for g_mkdir
fix inverted return value check for g_mkdir

neuschaefer/libgpod,hyperair/libgpod,hyperair/libgpod,neuschaefer/libgpod,neuschaefer/libgpod,hyperair/libgpod,neuschaefer/libgpod,neuschaefer/libgpod,hyperair/libgpod,hyperair/libgpod