db_test: don't verify SQLite issued error messages, they might change

A user on openbsc@ complained that with SQLite 3.8.2, the db_test fails with

  --- expected
  +++ stderr
  -DDB (2067) abort at 18 in [INSERT INTO subscriber (imsi) VALUES ($imsi)]: UNIQUE constraint failed: subscriber.imsi
  +DDB (2067) abort at 35 in [INSERT INTO subscriber (imsi) VALUES ($imsi)]: UNIQUE constraint failed: subscriber.imsi

i.e. a trivial difference in the error message issued by SQLite.

For db_test, don't output any SQLite error messages: Add argument
enable_sqlite_logging, pass as true, except in db_test.c.
Remove the SQLite error messages from expected output.

(Note that there is a src/db_test.c program that's not of interest here, this
is about the tests/db/db_test.c)

Change-Id: I2513d71cc0072aef8d08f47d0a1959f311176229
diff --git a/src/db_test.c b/src/db_test.c
index 0e823f9..7891c90 100644
--- a/src/db_test.c
+++ b/src/db_test.c
@@ -62,7 +62,7 @@
 		exit(1);
 	}
 
-	g_hlr->dbc = db_open(NULL, "hlr.db");
+	g_hlr->dbc = db_open(NULL, "hlr.db", true);
 	if (!g_hlr->dbc) {
 		LOGP(DMAIN, LOGL_ERROR, "Error opening database\n");
 		exit(1);