Calling get_network fails the second time it is called with the same entryUrl

[ckniffen]

The endpoint /network/get_network/:entryUrl will return an error about duplicate keys when it is called with the same entry point twice and crawling hasn't occurred.

{
    "result": "error",
    "message": "insert into \"networks\" (\"entry\", \"id\", \"port\", \"unls\") values ($1, $2, $3, $4) - duplicate key value violates unique constraint \"networks_pkey\""
}

[ckniffen]

@mvadari Did #72 fix this issue?