BUG-981: improve RuntimeGeneratedMappingServiceImpl clarity

This clarifies some of the locking interactions and well as it isolates
privay value.

Change-Id: Ic8961c9f9d32307fdd582191cab55bc633d081c5
Signed-off-by: Robert Varga <rovarga@cisco.com>
(cherry picked from commit bad1ca8b7f23a5c4b921d0d5e35a80a662a2a7d7)
Signed-off-by: Robert Varga <rovarga@cisco.com>
BUG-981: RuntimeGeneratedMappingServiceImpl thread safety

This patch improves and documents thread safety of waiting for schema to
become available. There was an obvious race condition between schema
context change and registering for notification.

Change-Id: Ieb3999b3d6af5fbbee63015c92a87353a71229d7
Signed-off-by: Robert Varga <rovarga@cisco.com>
(cherry picked from commit 24ca20057be79f34de59cba657a10deac12eb7ca)
Signed-off-by: Robert Varga <rovarga@cisco.com>