SSH query command: Add --start n option to skip n changes

Change-Id: If5031ce1a91a4fa68828241f1dfcf0c54f58652e
SSH query command: Remove resume_sortkey query operator

Remove resume_sortkey from query command documentation that
was missed in I6a82965db.

Change-Id: Iecc1c4638322b8d74ed3ab84e5792b3c2b3c7da7