move headers to include/osmocom/hlr

Apply the same headers structure that we keep in most Osmocom source trees:
Keep noinst_HEADERS in include/osmocom/hlr and include them using
  #include <osmocom/hlr/*.h>

The only header kept in src/ is db_bootstrap.h, because it is generated during
build time. If it was built in include/osmocom/hlr, we would need db.o to
depend on db_bootstrap.h in a different subdir, which automake can't do well.

Change-Id: Ic912fe27f545b85443c5fb713d8c3c8aac23c9ad
diff --git a/tests/auc/auc_test.c b/tests/auc/auc_test.c
index e23cc02..cdbd0b7 100644
--- a/tests/auc/auc_test.c
+++ b/tests/auc/auc_test.c
@@ -29,8 +29,8 @@
 
 #include <osmocom/crypt/auth.h>
 
-#include "logging.h"
-#include "auc.h"
+#include <osmocom/hlr/logging.h>
+#include <osmocom/hlr/auc.h>
 
 #define comment_start() fprintf(stderr, "\n===== %s\n", __func__);
 #define comment_end() fprintf(stderr, "===== %s: SUCCESS\n\n", __func__);