(FACT-719) Fix invalid argument warning when reading raw dmi data

Even when /sys/firmware/dmi/entries/1-0/raw is readable according to
its permissions, the actual reading can still fail with EINVAL.  This
patch catches that exception and treats it as if the file had not been
marked readable in the first place.

To be on the safe side, only EINVAL is muted, so other error
conditions will still come through.
(FACT-727) Add meaningful operatingsystem fact values for Arista EOS

This commit adds support for Arista EOS within the operating system
set of facts. This includes the `os`, `operatingsystem`, `osfamily`
`operatingsystemmajrelease`, and `operatingsystemrelease` facts.
Merge pull request #805 from whopper/fact-728/win_release_6.x

(FACT-728) Update Windows OS release resolution for > 6.2.x kernels
Merge pull request #806 from whopper/fact-727/arista_linux

(FACT-727) Add meaningful operatingsystem fact values for Arista EOS
(PUP-3479) Update ffi to ~1.9.5

Ruby 2.1.x on Windows requires ffi 1.9.5+. Update the ffi dependency to
1.9.5.
Merge pull request #807 from MikaelSmith/task/master/PUP-3479-update-ffi

(PUP-3479) Update ffi to ~1.9.5
(FACT-680) Correctly detect ipv6 link-local addresses

The regex in lib/facter/ipaddress6.rb will incorrectly detect all
addresses with 'fe80' in them and identify them as link-local addresses.

Should only occur when addresses start with fe80:

Modified existing tests to include an address with fe80 in it.

spec tests
Merge pull request #798 from scfc/fix/master/dmi-invalid-argument

(FACT-719) Fix invalid argument warning when reading raw dmi data
Merge pull request #786 from obliadp/ipv6-linklocal

(FACT-680) Correctly detect ipv6 link-local addresses
(FACT-724) Discard stderr from system_profiler