logging: Move the logging test from OpenBSC into libosmocore

Add a testcase for the logging facility. The test is coming from
the OpenBSC code.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 1d1491e..aaad0c8 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -4,7 +4,7 @@
                  smscb/smscb_test bits/bitrev_test a5/a5_test		\
                  conv/conv_test auth/milenage_test lapd/lapd_test	\
                  gsm0808/gsm0808_test gsm0408/gsm0408_test		\
-		 gb/bssgp_fc_test
+		 gb/bssgp_fc_test logging/logging_test
 if ENABLE_MSGFILE
 check_PROGRAMS += msgfile/msgfile_test
 endif
@@ -48,6 +48,9 @@
 gb_bssgp_fc_test_SOURCES = gb/bssgp_fc_test.c
 gb_bssgp_fc_test_LDADD = $(top_builddir)/src/libosmocore.la $(top_builddir)/src/gb/libosmogb.la
 
+logging_logging_test_SOURCES = logging/logging_test.c
+logging_logging_test_LDADD = $(top_builddir)/src/libosmocore.la
+
 # The `:;' works around a Bash 3.2 bug when the output is not writeable.
 $(srcdir)/package.m4: $(top_srcdir)/configure.ac
 	:;{ \
@@ -73,7 +76,9 @@
              lapd/lapd_test.ok gsm0408/gsm0408_test.ok			\
              gsm0808/gsm0808_test.ok gb/bssgp_fc_tests.err		\
              gb/bssgp_fc_tests.ok gb/bssgp_fc_tests.sh			\
-             msgfile/msgfile_test.ok msgfile/msgconfig.cfg
+             msgfile/msgfile_test.ok msgfile/msgconfig.cfg		\
+             logging/logging_test.ok logging/logging_test.err
+
 TESTSUITE = $(srcdir)/testsuite
 
 check-local: atconfig $(TESTSUITE)