Make Sentry version agree in 6.x branch config scripts.
Make Sentry version agree in 6.x branch config scripts.

This relates to the upstream change here:
http://github.mtv.cloudera.com/CDH/Impala/commit/c3580980

The upstream Sentry version is 2.1.0. The downstream script
impala-config-branch.sh still referenced 2.0.0.

Change-Id: I4f8eff8354b14027506cad2cb99591dde709d9c1
Reviewed-on: https://gerrit.sjc.cloudera.com/38309
Reviewed-by: Philip Zeyliger <3ba3974e96044dcde818e6310ed799abe10671d4@cloudera.com>
Reviewed-by: Stephen Moist <9b3f15cecebc7350bc212c734c28e8d5c36e8f73@cloudera.com>
Tested-by: David Knupp <6014aa7b8711b3b616d04da7c5083e463b5c51c9@cloudera.com>

cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala