BUG-981: improve waitForSchema() reliability

SchemaLock.waitForSchema() should not check presence of codecs, but
rather only look at available definitions. Rework it such that it is
more useful.

Change-Id: I0e6240dad78d1e4987b3c7e8b4171b0e117e4792
Signed-off-by: Robert Varga <rovarga@cisco.com>
(cherry picked from commit 45cb621d8fe559f9ef8db5b3e2bbf581f556fba3)
Signed-off-by: Robert Varga <rovarga@cisco.com>
BUG-987: ConstraintDefinitionImpl should be static

Change-Id: I22e61fc030b0a4e004bb078c4ea29b950a9b7f7b
Signed-off-by: Robert Varga <rovarga@cisco.com>
(cherry picked from commit af459f301bde9e87fd7b566e3e07c6a0033a14c5)
Signed-off-by: Robert Varga <rovarga@cisco.com>