Do not install tmux

Without this patch, tmux is installed on all the nodes, but
never used.

This is a problem, because some distributions of those three
families (for example SLE) may have decided to not ship tmux
because they ship some other terminal emulator, for example screen.

This patch solves the problem by removing the package that is not
used in any way.

Change-Id: I29f78be4c692fc276e82c3eb71a237614dd7cca0

tests/roles/bootstrap-host/vars/redhat.yml

@@ -28,7 +28,6 @@ packages_install:
   - python-devel
   - sshpass
   - systemd-networkd
-  - tmux
   - vim
   - xfsprogs
 

tests/roles/bootstrap-host/vars/suse.yml

@@ -28,7 +28,6 @@ packages_install:
   - lvm2
   - python
   - python-devel
-  - tmux
   - vim
   - vlan
   - xfsprogs

tests/roles/bootstrap-host/vars/ubuntu.yml

@@ -31,7 +31,6 @@ packages_install:
   - python2.7
   - python-dev
   - sshpass
-  - tmux
   - vim
   - vlan
   - xfsprogs