Bug 903403

It is suspected that host name resolution can fail in /etc/hosts under some circumstances.
We aim to work around this problem by forcing an tolerant encoding when using the Hosts resolver.
Tweak error message.

Also, do not treat ResolvError any dfiferently from any other StandardError.
Spec for Bug 903403.
Specs for RHC::Helpers.hosts_file_contains?

Code coverage should be complete.
Clean up
Merge pull request #295 from BanzaiMan/bz903403

Bug 903403