MB-21923: Always print number of docs in couch_dbinfo
MB-21923: Always print number of docs in couch_dbinfo

- Previously if there were no active (i.e non-deleted) documents in
  a couchstore file then couch_dbinfo would print the message
  "no documents".
- This means that if there are deleted documents in a file but 0
  non-deleted documents, the information about how many deleted
  docs there are is lost.
- This commit updates couch_dbinfo to always print out the number
  of deleted and non-deleted docs, as well as the size. This
  should not break any previous functionality as it will just
  display 0 if the file contains no documents.

Change-Id: If76a277629066fcdbf4c7b479d1426b13c4b432e
Reviewed-on: http://review.couchbase.org/70724
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Patrick Varley <cbb7353e6d953ef360baf960c122346276c6e320@couchbase.com>

couchbaselabs/couchstore,couchbaselabs/couchstore,couchbaselabs/couchstore