mod_gsmopen: remove binaries from tree

src/mod/endpoints/mod_gsmopen/.gitignore

 !/gsmlib/gsmlib-*/aclocal.m4
 !/gsmlib/gsmlib-*/configure
-!/gsmlib/gsmlib_1.10.orig.tar.gz

src/mod/endpoints/mod_gsmopen/gsmlib/README

 For Linux distros without gsmlib (eg: CentOS):
 
-Here are the original (ancient) sources for gsmlib, and the patch made by Ubuntu for modern compilers.
+In the directory gsmlib-1.10-patched-13ubuntu is the source for gsmlib
+as patched by Ubuntu for modern compilers:
 
-In the directory gsmlib-1.10-patched-13ubuntu are the patched sources, ready for (no need to patch them again):
 	./configure
 	make
 	make install