The previous gprs/protocol/gsm_04_60.h header from libosmogsm was
misleading because it was placed in the subdirectory used by libosmogb,
and hence was recently deprecated in favour of gsm/protocol/gsm_04_60.h.
Let's follow the pragma message advising to move to the new header file.
Depends: libosmocore 0158b05337a825352d9fd7f074170b686e9fd1e5
Change-Id: I027abbf3ed4c71331000565af1ef4f08f10cfafc