PHOENIX-1357 Salt sequence table to prevent same RS from getting all sequence calls

Conflicts:
	phoenix-core/src/main/java/org/apache/phoenix/coprocessor/MetaDataProtocol.java
	phoenix-core/src/main/java/org/apache/phoenix/query/ConnectionQueryServicesImpl.java
PHOENIX-1361 Sequence value goes backwards if sequence validated before reserved

Conflicts:
	phoenix-core/src/main/java/org/apache/phoenix/coprocessor/MetaDataEndpointImpl.java
	phoenix-core/src/main/java/org/apache/phoenix/query/ConnectionQueryServicesImpl.java
Use non zero thread pool depth for tests