https://jira.hyperledger.org/browse/FAB-1318

This completes the work begun with https://gerrit.hyperledger.org/r/#/c/2973
https://gerrit.hyperledger.org/r/#/c/2945/

.

The command
    peer chaincode upgrade -n mycc -p <upgrade chaincode path> -c '{"Args":[<args to upgrade chaincode>]}'

will upgrade exisisting chaincode "mycc" if one exists.

There is still work left on the committer side to comb block
for transactions colliding with an upgrade. Upgrade will override those
colliding transactions for that <chain, chaincode>. This will be in
a future CR when ledger and committer support for this work
is available.

A chaincode is uniquely identified by (chain name, chaincode name).
When upgrading a chaincode, many versions of the chaincode may be
running (typically 2, the "current" and the "upgrade" but one can
imagine multiple upgrades of the same chaincode in progress. Even
if only one will succeed...).

When upgrading, LCCC bumps up the version number for that chaincode.
This version is used to dissambiguate different versions of the
chaincode in a chain, just as chain id dissambiguated the chaincode among
different chains.

Chaincode framework will panic if version is not specified or not found.

Change-Id: Ie0e11cf4ed1263f91c8399021ea65a3e877e08ba
Signed-off-by: Srinivasan Muralidharan <muralisr@us.ibm.com>