perl: Rename lookup function to be more consistent with the Python bindings

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

src/perl/Location/Location.xs

@@ -57,7 +57,7 @@ init(file)
 		RETVAL
 
 char*
-get_country_code(db, address)
+lookup_country_code(db, address)
 	struct loc_database* db;
 	char* address;