call which from virtualbox scripts

[Vasiliy Pleshakov]

Despite of commentary at actions/prepare-environment.sh virtualbox script calls which in several places:
# grep -rn which *
actions/prepare-environment.sh:22:# We are avoiding using 'which' because of http://stackoverflow.com/questions/592620/check-if-a-program-exists-from-a-bash-script
actions/prepare-environment.sh:70:sshs=`which ssh | wc -l`
actions/prepare-environment.sh:89: ipconfigs=`which ipconfig | wc -l`
functions/memory.sh:25: if [ "$(which free)" != "" ]; then
functions/memory.sh:28: elif [ "$(which top)" != "" ]; then
functions/memory.sh:36: if [ "$(which sysctl)" != "" ]; then
functions/memory.sh:45: if [ "$(which free)" != "" ]; then
functions/memory.sh:48: elif [ "$(which top)" != "" ]; then

In all places we should use type instead of which:
type foo >/dev/null 2>&1

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/151676

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/151676
Committed: https://git.openstack.org/cgit/stackforge/fuel-main/commit/?id=5ac64a8c007eafd2001e7f529f1152587e0955a0
Submitter: Jenkins
Branch: master

commit 5ac64a8c007eafd2001e7f529f1152587e0955a0
Author: Serhiy Ovsianikov <email address hidden>
Date: Fri Jan 30 17:08:04 2015 +0200

    Call which from virtualbox scripts

    The "which" command is replaced with the "type" command. The free
    memory check error on the host has been fixed.

    Change-Id: I2cb8d143616372b649d51b9543160d40e5f2f510
    Closes-Bug: #1415685