misc: Use the osmo_init code for signals and logging

Use the libosmocore code to ignore certain signals by
default (e.g. SIGHUP, SIGPIPE) and use the new code to
create a default stderr logging target and initialize
it properly.
diff --git a/openbsc/tests/mgcp/mgcp_test.c b/openbsc/tests/mgcp/mgcp_test.c
index e2ed4e2..b7273de 100644
--- a/openbsc/tests/mgcp/mgcp_test.c
+++ b/openbsc/tests/mgcp/mgcp_test.c
@@ -20,6 +20,7 @@
 #include <openbsc/mgcp.h>
 #include <openbsc/mgcp_internal.h>
 
+#include <osmocom/core/application.h>
 #include <osmocom/core/talloc.h>
 #include <string.h>
 
@@ -74,11 +75,7 @@
 
 int main(int argc, char **argv)
 {
-	struct log_target *stderr_target;
-	log_init(&log_info);
-	stderr_target = log_target_create_stderr();
-	log_add_target(stderr_target);
-	log_set_all_filter(stderr_target, 1);
+	osmo_init_logging(&log_info);
 
 	test_auep();
 	return 0;