The peer channel fetch command has multiple problems.

1. It claims to fetch the configuration block, but actually fetches only
the genesis block.

2. The seekHelper in the deliver code claims to accept a seek position
start index, and returns one block, but in fact always seeks from oldest
to maxuint64 returning an infinite number of blocks.

3. The command outputs to a fixed filename (varying only by channel
name).

This CR fixes all three of these problems.

Change-Id: Ibd6c041f88f736b1948a12d81ee49ce6fe42538a
Signed-off-by: Jason Yellick <jyellick@us.ibm.com>