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/hlr_ussd.c b/src/hlr_ussd.c
index 1568815..00023ba 100644
--- a/src/hlr_ussd.c
+++ b/src/hlr_ussd.c
@@ -29,12 +29,12 @@
 #include <string.h>
 #include <errno.h>
 
-#include "hlr.h"
-#include "hlr_ussd.h"
-#include "gsup_server.h"
-#include "gsup_router.h"
-#include "logging.h"
-#include "db.h"
+#include <osmocom/hlr/hlr.h>
+#include <osmocom/hlr/hlr_ussd.h>
+#include <osmocom/hlr/gsup_server.h>
+#include <osmocom/hlr/gsup_router.h>
+#include <osmocom/hlr/logging.h>
+#include <osmocom/hlr/db.h>
 
 /***********************************************************************
  * core data structures expressing config from VTY
@@ -317,7 +317,7 @@
  * Internal USSD Handlers
  ***********************************************************************/
 
-#include "db.h"
+#include <osmocom/hlr/db.h>
 
 static int handle_ussd_own_msisdn(struct osmo_gsup_conn *conn, struct ss_session *ss,
 				  const struct osmo_gsup_message *gsup, const struct ss_request *req)