[master] use shorter path to msgq socket file

This fixes problem with
	socket.error: AF_UNIX path too long
on many builders.
(That is ticket #360.)

src/bin/stats/tests/Makefile.am

@@ -22,7 +22,7 @@ endif
 	$(LIBRARY_PATH_PLACEHOLDER) \
 	PYTHONPATH=$(COMMON_PYTHON_PATH):$(abs_top_builddir)/src/bin/stats:$(abs_top_builddir)/src/bin/stats/tests:$(abs_top_builddir)/src/bin/msgq:$(abs_top_builddir)/src/lib/python/isc/config \
 	B10_FROM_SOURCE=$(abs_top_srcdir) \
-	BIND10_MSGQ_SOCKET_FILE=$(abs_top_builddir)/src/bin/stats/tests/msgq_socket_test \
+	BIND10_MSGQ_SOCKET_FILE=$(abs_top_builddir)/msgq_socket \
 	CONFIG_TESTDATA_PATH=$(abs_top_srcdir)/src/lib/config/tests/testdata \
 	$(PYCOVERAGE_RUN) $(abs_srcdir)/$$pytest || exit ; \
 	done