SLES support

[deric]

Verify functionality and add SLES to supported systems.

[deric]

@redno2 I've created a Docker image for testing purposes. On Docker hub there are official images of opensuse 13.2 and 42.2.

Currently most of the tests are passing:

  1) YAML declaration avoid cyclic dependency Command "groups jordi" stdout should match /jordi : jordi/
     Failure/Error: its(:stdout) { is_expected.to match /jordi : jordi/ }
       expected "jordi : users sudo it\n" to match /jordi : jordi/
       Diff:
       @@ -1,2 +1,2 @@
       -/jordi : jordi/
       +jordi : users sudo it
       
       
     # ./spec/acceptance/hiera_spec.rb:132:in `block (4 levels) in <top (required)>'

  2) YAML declaration avoid cyclic dependency Command "groups it" stdout should match /it : it sudo/
     Failure/Error: its(:stdout) { is_expected.to match /it : it sudo/ }
       expected "it : users sudo it\n" to match /it : it sudo/
       Diff:
       @@ -1,2 +1,2 @@
       -/it : it sudo/
       +it : users sudo it
       
       
     # ./spec/acceptance/hiera_spec.rb:139:in `block (4 levels) in <top (required)>'

  3) accounts defintion manage users Command "id -g deployer" stdout should match /1010/
     Failure/Error: its(:stdout) { is_expected.to match /1010/ }
       expected "100\n" to match /1010/
       Diff:
       @@ -1,2 +1,2 @@
       -/1010/
       +100

I'm gonna look into the failures later, hopefully it won't be hard to fix.