db_redis: use SHARE_DIR define for default value of schema path param

- point to the folder where the schema files are deployed by make
install

src/modules/db_redis/db_redis_mod.c

@@ -32,7 +32,7 @@
 MODULE_VERSION
 
 str redis_keys = str_init("");
-str redis_schema_path = str_init("/usr/share/kamailio/db_redis/kamailio");
+str redis_schema_path = str_init(SHARE_DIR "db_redis/kamailio");
 int db_redis_verbosity = 1;
 
 static int db_redis_bind_api(db_func_t *dbb);