CLOUDSTACK-7565: Fixes to avoiding QEMU issue in attach volume operation by changing test case steps

Signed-off-by: SrikanteswaraRao Talluri <talluri@apache.org>
CID-1116231: Use implicit lock, synchronize _key in Link

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
CID-1233090, CID-1233089: Synchronize on session object in ApiServer

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
CID-1116258: Guard _storagePools using synchronized in KVMStoragePoolManager

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
CID-1116250: Lock on s_appContextDelegates before calling get in ComponentContext

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
CID-1116248: Synchornize method in SynchronousListener

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
CID-1116245: Lock for getting answers from SynchronousListener

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
CLOUDSTACK-7184: xenheartbeat gets passed timeout and interval
(cherry picked from commit 4d065b9a3a336d59902c266202c1094509c007d2)

Conflicts:
	plugins/hypervisors/xenserver/src/com/cloud/hypervisor/xenserver/discoverer/XcpServerDiscoverer.java
	plugins/hypervisors/xenserver/src/com/cloud/hypervisor/xenserver/resource/CitrixResourceBase.java
	server/src/com/cloud/configuration/Config.java
	server/src/com/cloud/configuration/ConfigurationManagerImpl.java
	server/src/com/cloud/resource/DiscovererBase.java
CLOUDSTACK-7527 reboot faster by writing to /proc/sysrq-trigger

(cherry picked from commit d04f59a30d130dbb83f162af6e67334fe2c9cef0)
CLOUDSTACK-7184 retry-wait loop config to deal with network glitches

(cherry picked from commit a29f954a269c992307f0410df88ca4ac7a0b82a0)

Conflicts:
	engine/orchestration/src/com/cloud/agent/manager/DirectAgentAttache.java