in openair2/ENB_APP/enb_config.c
it was tested against 63, it should be tested against 15
no impact on processing whatsoever so no need to test

Line 4 of *.h files depends on the directory containing openair;
get rid of it.

Also modified CMakeLists.txt to run asn1tostruct.py at cmake time,
because the generated Makefile was wrong. When compiling with -j4
it would mess up by calling fix_asn1 twice with a weird timing,
leading to failures.

The strategy is rather basic. Files with warnings are replaced
by an edited copy that triggers no warning.

We take care to check that the replaced file is the same as the
one that was analyzed at the time of warning removal (through
checking its SHA1).

There is a new bash script "fix_asn1" in cmake_targets/tools
and the files replacing the existing ones are in
cmake_targets/tools/fix_asn1.data.