Create a new connection when a process fork has been detected

This patch attempts to deal with applications that have forked the
process after connecting to the broker.  First, the creation of the
connection is delayed until the application attempts to perform a
messaging operation.  Second, each time the application performs a
messaging operation the current process id is checked against the id
of the process that created the connection.  If the process ids do not
match, the application has called os.fork().  The new child process
discards the existing connection and creates a new one.

Change-Id: I5455cb0f8d380d6b65f1268b34a91355cbb14aa2
Closes-Bug: #1392868
Merge "Create a new connection when a process fork has been detected"