Fix for #2267
During UVE sync, the UVE object is initialized with the sandesh_global instance during creation.
If the sandesh client doesn't call init_generator() on the sandesh_global instance, then the sandesh_global
instance will have empty source, node_type, module and instance_id. Therefore, UVE object initialized with
the sandesh_global instance will be sent with empty source, node_type, module and instance_id in the sandesh header.
This results in improper addition/updation/deletion of UVEs in redis.
In sync_uve(), pass sandesh_instance while creating UVE object.
Merge pull request #15 from Juniper/sundar_2267

Fix for #2267
Patch in:
commit 69c88b64701caaac414bbc753061dfd86094c518
Author: Megh Bhatt <meghb@juniper.net>
Date:   Thu Dec 19 15:46:39 2013 -0800

    1. Fix potential memory corruption caused by accessing and modifying
       last_event in SandeshStateMachine and SandeshClientSM from
       concurrent threads by using the state machine mutex.
    2. Consolidate state machine event statistics into a common
       structure - SandeshEventStatistics - sandesh_statistics.h
       and let both SandeshStateMachine and SandeshClientSM use it.
Patch in:
commit 6f425af08f02ed6c6bf676c25864ed0f0d3554ad
Author: Megh Bhatt <meghb@juniper.net>
Date:   Tue Jan 21 14:11:39 2014 -0800

    1. Allow generators to not start HTTP introspect by passing
       -1 as HTTP port in init_generator pysandesh
    2. Add UveInterVnStats, InterVnStats, virutalmachine_list to
       UveVirtualNetworkAgentTrace message in mock generator
    3. Allow user to specify number of instances per generator
       and number of virtual networks
Merge pull request #16 from Juniper/meghb_missed

Patch in: 69c88b64701caaac414bbc753061dfd86094c518 missed commit
Patch in:
commit 6f425af08f02ed6c6bf676c25864ed0f0d3554ad
Author: Megh Bhatt <meghb@juniper.net>
Date:   Tue Jan 21 14:11:39 2014 -0800

    1. Allow generators to not start HTTP introspect by passing
       -1 as HTTP port in init_generator pysandesh
    2. Add UveInterVnStats, InterVnStats, virutalmachine_list to
       UveVirtualNetworkAgentTrace message in mock generator
    3. Allow user to specify number of instances per generator
       and number of virtual networks
Merge pull request #17 from Juniper/meghb_mock

Patch in: 6f425af08f02ed6c6bf676c25864ed0f0d3554ad
Logger name should be the generator id (source, module, node type,
instance id) rather than just the module
Merge pull request #18 from Juniper/meghb_mock_1

Logger name should be the generator id
enable logging to file when sandesh connection is not established
Merge pull request #19 from Juniper/rajreddy_sandesh_log

enable logging to file when sandesh connection is not established
syslog fields are optional
Merge pull request #20 from Juniper/syslogfix

syslog fields are optional