build: tests: don't link system installed libosmogsm.

Add src/gsm/libosmogsm.la explicitly to some test linkages, because otherwise
the linker would pick the libosmogsm already installed on the system instead of
the one that was just built in the source tree.

I noticed because a libosmogsm needing some more symbols from libosmocodec was
still installed, while the patch that cause it was already removed. Thus I
caught all(?) test binaries that linked libosmogsm from $PREFIX.

Change-Id: Ie61d60e1506f16de20add70fd0f44ebfa7a00a75
1 file changed