xenapi: glance plugin should close connections

Current the xenapi glance plugin does not close
httplib connections when exceptions are raised.

Note this code is run under python 2.4 so with
is not available.

Fixes bug 1197846

Change-Id: I5cfb067320e7506109c301532a95fe83aa4fd0f9
Fix cells manager rpc api version

405ebb90 added version 1.11 to the rpc API, but the cells manager did
not get updated.

Change-Id: I400db9229e88dc3e8e2fbb24c6adae7b070d12cd
Merge "xenapi: glance plugin should close connections"
Merge "Fix cells manager rpc api version"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp