src: use new library libosmogsm and new path to headers in libosmocore

libosmogsm is a new library that is distributed in the libosmocore.
Now, openbsc depends on it. This patch gets openbsc with this
change.

This patch also rewrites all include path to the new
osmocom/[gsm|core]

Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>
diff --git a/openbsc/include/openbsc/gprs_gmm.h b/openbsc/include/openbsc/gprs_gmm.h
index bd129ae..f6b3e5e 100644
--- a/openbsc/include/openbsc/gprs_gmm.h
+++ b/openbsc/include/openbsc/gprs_gmm.h
@@ -1,7 +1,7 @@
 #ifndef _GPRS_GMM_H
 #define _GPRS_GMM_H
 
-#include <osmocore/msgb.h>
+#include <osmocom/core/msgb.h>
 #include <openbsc/gprs_sgsn.h>
 
 int gsm48_tx_gsm_deact_pdp_req(struct sgsn_pdp_ctx *pdp, uint8_t sm_cause);