Command line option to pass username or password doesn't work with multi-controller job files

[alexafshar]

If job file contains multiple controllers configured, command line option "-u" or "-p" will error out.
Its fair to say, command line options -u, -p will only support single controller job files for now. Will update install instructions to this effect for now. To that end, will need to mitigate by notifying users that use -u or -p that this is not supported IF they have multiple controllers defined in the job file. see #45