Fix or remove version checking in MongoRunner.runMongoTool()

MongoRunner.getBinVersionFor(opts.binVersion) === '' will never return true after the changes from SERVER-23547 and therefore never pass the --dialTimeout to the mongo tool. The --dialTimeout command line option was backported to the 3.2 and 3.0 version of the mongo tools, which may obviate the need for version checking if we aren't concerned about testing particular minor versions of the tools against the server.