run_cqlsh: disable color output
run_cqlsh: disable color output

We try to get keyspaces' name from cqlsh output, the color string will
introduce wrong keyspace name.

Running 'cqlsh -e "select keyspace_name from system_schema.keyspaces" 10.142.0.45 --request-timeout=60'
[stdout]  ESC[0;1;31mkeyspace_nameESC[0m
[stdout] --------------------
[stdout]         ESC[0;1;33msystem_authESC[0m
[stdout]       ESC[0;1;33msystem_schemaESC[0m
[stdout]           ESC[0;1;33mkeyspace1ESC[0m
[stdout]  ESC[0;1;33msystem_distributedESC[0m
[stdout]              ESC[0;1;33msystemESC[0m
[stdout]       ESC[0;1;33msystem_tracesESC[0m
[stdout]
[stdout] (6 rows)

Running 'nodetool cfstats ESC[0;1;33mkeyspace1ESC[0m'
[stdout] nodetool: Unknown keyspace: ESC[0
[stdout] See 'nodetool help' or 'nodetool help <command>'.
[stdout] bash: 1: command not found
[stdout] bash: $'33mkeyspace1\E[0m': command not found

Signed-off-by: Amos Kong <eb01d8f828a6c9a20be4534e72e049aaf41503df@scylladb.com>

scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,amoskong/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,amoskong/scylla-cluster-tests,amoskong/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-longevity-tests,amoskong/scylla-cluster-tests,scylladb/scylla-cluster-tests,amoskong/scylla-cluster-tests