(packaging) Update PUPPETVERSION to 3.5.0-rc1
(PUP-1954) use attr_accessor instead of attr

A one-line change that fixes a deprecation warning on certain versions
of ruby, including jruby.

Stackoverflow says this code is equivalent:

http://stackoverflow.com/questions/13958061/attr-vs-attr-accessor
Merge tag '3.5.0-rc1'

3.5.0-rc1

* tag '3.5.0-rc1':
  (packaging) Update PUPPETVERSION to 3.5.0-rc1
Merge pull request #2434 from KevinCorcoran/fix-deprecation-warning

(PUP-1954) use attr_accessor instead of attr
(pup-1952) Add jruby-19mode to travis ci (but under allow_failures)
(pup-1952) Break out jruby versions of gems as needed
(pup-1952) Accomodate that jruby can't fork