Update sam/sam-agent/src/main/java/org/talend/esb/sam/agent/eventproducer/EventProducerInterceptor.java

operationName.equals(SAM_OPERATION)
==>
SAM_OPERATION.equals(operationName)
to void null Exception.
Merge pull request #11 from ttoommbb/master

Try to add SAM fupport for REST Service, has error.