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/src/auc.c b/src/auc.c
index 79c3918..28c441f 100644
--- a/src/auc.c
+++ b/src/auc.c
@@ -23,8 +23,8 @@
 #include <osmocom/core/utils.h>
 #include <osmocom/crypt/auth.h>
 
-#include "logging.h"
-#include "rand.h"
+#include <osmocom/hlr/logging.h>
+#include <osmocom/hlr/rand.h>
 
 #define hexb(buf) osmo_hexdump_nospc((void*)buf, sizeof(buf))
 #define hex(buf,sz) osmo_hexdump_nospc((void*)buf, sz)