drmgr doesn't reject unrecognized arguments

[nathanlynch]

E.g.

[root@ltcden12-lp12 ~]# drmgr abc -c mem def -r deadbeef
Validating Memory DLPAR capability...yes.
DR_TOTAL_RESOURCES=1

I have one report of an invocation like this:

drmgr -c mem -r 2

resulting in a successful removal of zero memory, but I haven't recreated that (this just results in removing one LMB in my attempts).

drmgr's argument parsing should error out in such circumstances.