Fix Index Count in Timekeeper

Now sendStreamUpdateForDropIndex in indexer.go is taking care of
removing index from maint stream in drop index. So there is no
need to automatically do it in timekeeper.

Change-Id: Ibd07460a6be309d11714025850c776a7b7b8b01d
Reviewed-on: http://review.couchbase.org/43841
Reviewed-by: Pratap Chakravarthy <prataprc@couchbase.com>
Reviewed-by: Deepkaran Salooja <deepkaran.couchbase@gmail.com>
Tested-by: Deepkaran Salooja <deepkaran.couchbase@gmail.com>