[OE-core] [PATCH] Fix RPATH warning vs. weird paths

[Andy Ross]

We hit some oddball cases where libraries were being built with RPATHs
referencing host directores and causing version skew in builds.  There
is a warning case to detect that already, but it was being fooled by
".." terms in the path strings.  This just adds a normalize step to
the path comparison and unmasks the missing warnings.

Andy