CLOUDSTACK-4334. Documentation for how to write an object store plugin.
CLOUDSTACK-4436: in case of older kvm host, we'd better try serveral times to make sure we passed cmdline parameters to system vms
CLOUDSTACK-4089: UI > zone wizard > hypervisor VMware > configure physical network > edit traffic type label > split "VMware Traffic Label" field into 3 fields: "vSwitch Name", "VLAN ID", "vSwitch Type".
Not everyone wants to use Mutual CHAP with VMware - make it optional.
Merge remote-tracking branch 'upstream/4.2-forward' into 4.2-forward

Make Mutual CHAP optional.