ACCUMULO-1691 Support Thrift 0.9.1

  Enforce version 0.9.1 until THRIFT-2173 is implemented, and provide a custom
  server so we can access the underlying transport to get the client address.
ACCUMULO-2773 Regenerate sources for Thrift 0.9.1
Merge branch '1.6.1-SNAPSHOT'

Conflicts:
	core/src/main/java/org/apache/accumulo/core/data/thrift/MultiScanResult.java
	core/src/main/java/org/apache/accumulo/core/data/thrift/ScanResult.java
	core/src/main/java/org/apache/accumulo/core/data/thrift/TConditionalMutation.java
	core/src/main/java/org/apache/accumulo/core/data/thrift/TMutation.java
	core/src/main/java/org/apache/accumulo/core/data/thrift/UpdateErrors.java
	server/base/src/main/java/org/apache/accumulo/server/util/TServerUtils.java