Fixing logic error in app recipe

if the dir node[:berkshelf_api][:home] is not there when creating the
user (which uses node[:berkshelf_api][:home] as it’s homedir), useradd
fails and breaks the CCR
Successfully tested on CentOS and RHEL

Only requirement for those platforms is the use of build-essentials >=
2.0.2 So not sure if this is a accepted way of adding that dependency,
but with this you got a working stack for RHEL, CentOS and Ubuntu…
Merge pull request #118 from svanharmelen/Bugfixing

Fixing logic error in app recipe