vm: make sure qmemman connection is closed even on failed VM startup
vm: make sure qmemman connection is closed even on failed VM startup

Qmemman hold global lock while serving requests, so not closing
connection will prevent any further action.

woju/qubes-core-admin,woju/qubes-core-admin,QubesOS/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,woju/qubes-core-admin,woju/qubes-core-admin,QubesOS/qubes-core-admin,marmarek/qubes-core-admin,marmarek/qubes-core-admin