Revert "Adds Warning when NetworkManager is active on hosts"

This reverts commit 2faa9a2cb616615f189a7ed6a7eade9a9f12c0e6.

Fixes: rhbz#1117277
Signed-off-by: Gael Chamoulaud <gchamoul@redhat.com>

Conflicts:
	packstack/plugins/neutron_350.py

Change-Id: I12fb82607b6dedf429954325b31aac0148fd1092
Merge "Revert "Adds Warning when NetworkManager is active on hosts""