ledger

For a while composer has created composite keys in a specific
format and this has worked fine. Since the introduction of a
change to the GetState protocol, GetState has not been returning
information.

Additional investigation showed that the error occurs due to a
bad URL generated when then key contains a colon ":"

Problem is resolved by encoding the path using url EscapedPath()
method instead of the String() method.

Change-Id: I20ad8177301ea845dd234eb867c95b5cde7a908c
Signed-off-by: Chris Elder <chris.elder@us.ibm.com>