BUG-509: Fail forwarning write if read fails.

This primarily gets rid of e.printStackTrace(), but as part of that it
defines an important thing: if a read fails while we're building up the
path, we should not try to continue with the operation.

Change-Id: I48cb6cd304a98684a6984d26b6fc8dd5d14963c5
Signed-off-by: Robert Varga <rovarga@cisco.com>
BUG-509: improve normalization error reporting

This patch introduces an explicit checked exception for reporting
normalization errors, declares it at strategic places and makes use of
it for generating better error reports than:

Caused by: java.lang.IllegalArgumentException: Supplied QName (urn:opendaylight:params:xml:ns:yang:pcep:crabbe:initiated:00?revision=2014-01-13)initiation is not valid according to schema container stateful

Change-Id: I2020c9e6ef85035259558a32f141a132b6321e0e
Signed-off-by: Robert Varga <rovarga@cisco.com>