Fixed RPL warnings.

There were a few variables that were set but never used, and it's time
to get those out so I don't have to ignore all the warnings.
Fixed tabs and whitespace.

Someone edited a lot of files with a text editor that, for whatever
reason that is unclear to me, doesn't change its tab settings to the
obvious tab settings of the document being edited. The person then used
8 character wide tabs when 8 spaces should have used, and an intelligent
editor makes it look terrible.
Merge branch 'rpl-no-warning'

Conflicts:
	tos/lib/net/blip/IPForwardingEngineP.nc