Rename bsc_nat -> osmo-bsc_nat and bsc_mgcp -> osmo-bsc_mgcp

This now enforces a unique structure: All of our main daemon
programs start with an "osmo-" prefix.
diff --git a/openbsc/src/Makefile.am b/openbsc/src/Makefile.am
index e4b2b96..1a8ec64 100644
--- a/openbsc/src/Makefile.am
+++ b/openbsc/src/Makefile.am
@@ -2,17 +2,12 @@
 AM_CFLAGS=-Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOVTY_CFLAGS) $(COVERAGE_CFLAGS)
 AM_LDFLAGS = $(LIBOSMOCORE_LIBS) $(COVERAGE_LDFLAGS)
 
-SUBDIRS = common abis mgcp bsc trau osmo-nitb utils ipaccess gprs
+SUBDIRS = common abis mgcp bsc trau osmo-nitb osmo-bsc_mgcp utils ipaccess gprs
 
 # Conditional modules
 if BUILD_NAT
-SUBDIRS += nat
+SUBDIRS += osmo-bsc_nat
 endif
 if BUILD_BSC
 SUBDIRS += osmo-bsc
 endif
-
-bin_PROGRAMS = bsc_mgcp
-
-bsc_mgcp_SOURCES = mgcp/mgcp_main.c
-bsc_mgcp_LDADD = common/libcommon.a mgcp/libmgcp.a $(LIBOSMOVTY_LIBS)