Two fixes for RedHat:

- 'property' was renamed to 'prop', so fix the error message
- the 'netmask' as described in the README doesn't work on RedHat:
  NoMethodError: undefined method `length' for 24:Fixnum
  so use the "Debian-style" notation there too.
Merge pull request #57 from jasperla/redhat_fixes

Two fixes for RedHat:
Prevent restarting the network every time puppet runs b/c of default netmask

Since we retrieve the default netmask as '' but couldn't handle setting it
as '' we defaulted to '0.0.0.0' and ended up changing the netmask every single
puppet run. And thus we ended up restarting the network every time puppet ran.
Notice: /Stage[main]/Networks::Route/Network_route[default]/netmask: netmask changed '' to '0.0.0.0'
Merge branch 'pull-59'
Merge remote-tracking branch 'upstream/master'