Fix misc thread locking bugs / bogus warnings

Fix all thread locking bugs reported by object-locking test
case.

NB, some of the driver locking is getting too coarse. Driver
mutexes really need to be turned into RW locks instead to
significantly increase concurrency.

* src/lxc_driver.c: Fix useof driver when unlocked in the methods
  lxcDomainGetInfo, lxcSetSchedulerParameters, and
  lxcGetSchedulerParameters
* src/opennebula/one_driver.c: Fix missing unlock in oneDomainUndefine.
  Fix use of driver when unlocked in oneDomainGetInfo,
  oneGetOSType, oneDomainShutdown
* src/qemu_driver.c: Fix use of driver when unlocked in
  qemudDomainSavem, qemuGetSchedulerType, qemuSetSchedulerParameters
  and qemuGetSchedulerParameters
* src/storage_driver.c: Re-work storagePoolCreate to avoid bogus
  lock checking warning. Re-work storageVolumeCreateXMLFrom to
  remove a potential NULL de-reference & avoid bogus lock check
  warnings
* src/test.c: Remove testDomainAssignDef since it break lock chekc
  warnings.
* tests/object-locking.ml: Add oneDriverLock, oneDriverUnlock
  and one_driver_t methods/types to allow lock checking on the
   OpenNebula drivers

tests/object-locking.ml

@@ -128,7 +128,8 @@ let driverLockMethods = [
     "umlDriverLock";
     "nodedevDriverLock";
     "networkDriverLock";
-    "storageDriverLock"
+    "storageDriverLock";
+    "oneDriverLock"
 ]
 
 (*
@@ -142,7 +143,8 @@ let driverUnlockMethods = [
     "umlDriverUnlock";
     "nodedevDriverUnlock";
     "networkDriverUnlock";
-    "storageDriverUnlock"
+    "storageDriverUnlock";
+    "oneDriverUnlock"
 ]
 
 (*
@@ -159,6 +161,7 @@ let lockableDrivers = [
       "virStorageDriverStatePtr";
       "network_driver";
       "virDeviceMonitorState";
+      "one_driver_t";
 ]