URL DB Parsing Fails for +SRV URLs

[derekrprice]

My Mongo DSN looks like mongodb+srv://mongo:27017/dbname. Using this configuration yields an error about "$databaseName is not defined":

'mongo' => [
    'driver' => 'mongodb',
    'dsn' => 'mongodb+srv://mongo:27017/dbname',
]

Adding a database name to the configuration works around the issue, but it is redundant with the information in the URL:

'mongo' => [
    'driver' => 'mongodb',
    'dsn' => 'mongodb+srv://mongo:27017/dbname',
    'database' => 'dbname',
]

Bug #1861's fix fixed this problem for mongodb:// style URLs but its parser missed mongodb+srv://.