add ImageCacheManage class skel
skip firewall setup for unexistent ports

Sometimes neutron tries to tune iptables on non-existent
ports, so let's just print warning in this case.
remove function for nova firewall handling

Nova firewall in deprecated and even broken in pcs
driver, so let's completely remove all code, which
deals with it.
move *Templace classes to template.py file
rename prlconsts to pc

Constants from prlsdkapi module have too long names, together
will long 'prlconsts' it requires line breaks often.
Let's rename it to 'pc'.
move <un>compress_ploop to a new file utils.py

Some functions should be used in template.py, driver.py and
pcs-glance-tool. For example PCSDriver.snapshot method does
the same work as pcs-glance-tool. So let's add file utils.py,
which will contain some function, which can be used everywhere.
add compressed ploop support to pcs-glance-tool
unapck ploop to container's place with root helper

user nova can't chdir to a container directory.