Correct the exception type for Cluster test
Correct the exception type for Cluster test

It throws CouchbaseException, not ErrorException

Change-Id: I82aa56f61f6f947aa7c44fdec96d3b0c9f0395c1
Reviewed-on: http://review.couchbase.org/22670
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

couchbase/php-ext-couchbase,couchbase/php-ext-couchbase,couchbase/php-ext-couchbase,couchbase/php-ext-couchbase,couchbase/php-ext-couchbase