use osmo_init_logging2() with proper talloc ctx

There is a duality of initialization: early_init() in bts.cpp wants to init
logging even before static instances get initialized. Make sure that
tall_pcu_ctx is initialized during early_init() as well. There is a build
context that does not seem to include bts.cpp (osmo-pcu-remote), so to be sure,
init tall_pcu_ctx as NULL and both in early_init() as well as pcu_main.cpp,
init both tall_pcu_ctx and logging if it is still NULL.

Change-Id: I2199b62d0270bd35dec2283e8f5b364b7c63915b
diff --git a/tests/llc/LlcTest.cpp b/tests/llc/LlcTest.cpp
index eb693f5..3083644 100644
--- a/tests/llc/LlcTest.cpp
+++ b/tests/llc/LlcTest.cpp
@@ -225,7 +225,7 @@
 		abort();
 
 	msgb_talloc_ctx_init(tall_pcu_ctx, 0);
-	osmo_init_logging(&gprs_log_info);
+	osmo_init_logging2(tall_pcu_ctx, &gprs_log_info);
 	log_set_use_color(osmo_stderr_target, 0);
 	log_set_print_filename(osmo_stderr_target, 0);
 	log_set_log_level(osmo_stderr_target, LOGL_INFO);