remove lock

[lxning]

Issue #, if available:

Description of changes:

This changes is to remove the lock in function pollBatch(). The reason is that each WorkerThread calls pollBatch to get a batch requests from a LinkedBlockingDeque and load them into its own buffer. This lock is not necessary since LinkedBlockingDeque is thread safe.

Testing done:

The test was done at local environment. The test configuration:
inference_address=http://127.0.0.1:8080
management_address=http://127.0.0.1:8081
model_store=../modelarchive/src/test/resources/models
load_models=squeezenet_v1.1.mar
preload_model=true
default_workers_per_model=2
async_logging=true
default_response_timeout=120
unregister_model_timeout=120
max_request_size=10485760
enable_envvars_config=true
job_queue_size=100

Test case1:
#!/bin/bash begin=$(date +%s) for i in {1..10000} do #echo "Welcome $i times" curl -X POST localhost:8080/predictions/squeezenet_v1.1 -T kitten.jpg done end=$(date +%s) latency=expr $end - $endecho $begin echo $end echo $latency
Test case2: call the following scripts 10 concurrently.
#!/bin/bash begin=$(date +%s) for i in {1..1000} do #echo "Welcome $i times" curl -X POST localhost:8080/predictions/squeezenet_v1.1 -T kitten.jpg done end=$(date +%s) latency=expr $end - $endecho $begin echo $end echo $latency
To run CI tests on your changes refer README.md

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