Update CqlConsistency.cs

Extending CqlConsistency enum with the LocalOne (0x000A) consistency level based on https://git-wip-us.apache.org/repos/asf?p=cassandra.git;a=blob_plain;f=doc/native_protocol.spec;hb=refs/heads/cassandra-1.2
Merge pull request #44 from dbalazs/patch-1

Update CqlConsistency.cs