Added JID to log when failing to load PGP fingerprint

Added PGP stub for tests

tests/unittests/pgp/stub_gpg.c

@@ -30,6 +30,11 @@ char* p_gpg_sign(const char * const str, const char * const fp)
     return NULL;
 }
 
+gboolean p_gpg_valid_key(const char * const keyid)
+{
+    return FALSE;
+}
+
 gboolean p_gpg_available(const char * const barejid)
 {
     return FALSE;