Fix messages with new_size variables in logical_volume/lvm.rb
Fix Issue 14718 and 17920

Code as provided by Sander Hollaar in http://projects.puppetlabs.com/issues/14718
Problem is also described in http://projects.puppetlabs.com/issues/17920
Fix failed tests
Merge pull request #27 from raphink/messages

Fix messages with new_size variables in logical_volume/lvm.rb
Merge pull request #28 from raskas/master

Feature/14718: size 'undef' doesn't work when creating a new logical volume
adding support for lvcreate -l argument (extents)
adding tests and fixing the extents validation regex
fixed test failures due to improper method call assertion ordering
minor fix to text in test
Merge branch 'master' of https://github.com/nlloyd/puppetlabs-lvm