better support for Fedora 20; better VM_WAIT_FILE support; other fixes

Improve support for using virt-install and other virt tools on F20
Improve VM_WAIT_FILE support - in the config file, the VM_WAIT_FILE
should have 4 backslashes for every backslash in the actual file -
for example, if you want to create the file \installcomplete as the
VM_WAIT_FILE, set the following in your ad*.conf:
VM_WAIT_FILE=\\\\installcomplete
When retrieving the CA cert from AD, use the IP address of the
Windows machine instead of the hostname - if using a private network,
the Windows guest hostname may not be resolvable from the host.
Other fixes to use $SUDOCMD when testing for the existence of certain
files