kvm: Return capitalized NONE when no disk cache mode is set

This caused Instances not to start under rare circumstances
debian: Do not depend on tomcat for building

No need for Tomcat when building the packages
clean up XenServer resource code
avoid creating same primary storage multiple times for XenServer
Fixed few coverity issues

Signed-off-by: Santhosh Edukulla <santhosh.edukulla@gmail.com>
added created time for new added guest OSes
CloudStackCLOUDSTACK-7366
Baremetal agent is not including in RPM spec file
Support a new control for storage tags on the Add Compute Offering and Add Disk Offering windows