selboolean reports error if selinux is not enabled

If an selboolean is defined for a class, but is executing on a host that does not have SELinux enabled, an error is reported. e.g.:

Execution of '/usr/sbin/getsebool httpd_can_network_connect' returned 1: /usr/sbin/getsebool: SELinux is disabled

It should not be considered a failure, but perhaps a warning if you try to set/get an SELinux boolean on a host that does not have selinux enabled.

Before setting/getting the boolean, a quick call to getenforce could be made, and a warning issued if it returns "Disabled".