Install psmisc on Linux worker images to include fuser utility

The fuser utility is required for the worker image to properly
unmount the migrated disks from itself, thus preventing the mounted
partitions from throwing 'device is busy' errors.

coriolis/osmorphing/osmount/redhat.py

@@ -20,7 +20,7 @@ class RedHatOSMountTools(base.BaseLinuxOSMountTools):
 
     def setup(self):
         super(RedHatOSMountTools, self).setup()
-        self._exec_cmd("sudo -E yum install -y lvm2")
+        self._exec_cmd("sudo -E yum install -y lvm2 psmisc")
         self._exec_cmd("sudo modprobe dm-mod")
 
     def _allow_ssh_env_vars(self):

coriolis/osmorphing/osmount/ubuntu.py

@@ -18,7 +18,7 @@ class UbuntuOSMountTools(base.BaseLinuxOSMountTools):
     def setup(self):
         super(UbuntuOSMountTools, self).setup()
         self._exec_cmd("sudo -E apt-get update -y")
-        self._exec_cmd("sudo -E apt-get install lvm2 -y")
+        self._exec_cmd("sudo -E apt-get install lvm2 psmisc -y")
         self._exec_cmd("sudo modprobe dm-mod")
 
     def _allow_ssh_env_vars(self):