storage: Remove rwlocks during virStoragePoolObjListForEach

storage: Remove rwlocks during virStoragePoolObjListForEach

Remove the locks since they are unnecessary and would cause
a hang for a driver reload/restart when a transient pool was
previously active as a result of the call:

virStoragePoolUpdateInactive:
...
    if (!virStoragePoolObjGetConfigFile(obj)) {
        virStoragePoolObjRemove(driver->pools, obj);
...

stack trace:

Thread 17 (Thread 0x7fffcc574700 (LWP 12465)):
...pthread_rwlock_wrlock
...virRWLockWrite
...virObjectRWLockWrite
...virStoragePoolObjRemove
...virStoragePoolUpdateInactive
...storagePoolUpdateStateCallback
...virStoragePoolObjListForEachCb
...virHashForEach
...virStoragePoolObjListForEach
...storagePoolUpdateAllState
...storageStateInitialize
...virStateInitialize
...daemonRunStateInit
...virThreadHelper
...start_thread
...clone

Introduced by commit id 4b2e0ed6e3.

Signed-off-by: John Ferlan <jferlan@redhat.com>
ACKed-by: Michal Privoznik <mprivozn@redhat.com>