Modify config-api exceptions, bump config and netconf to 0.2.5-SNAPSHOT.

Change ConflictingVersionException and ValidationException to be checked instead of
runtime exceptions.
Fix ConfigPusher's ConflictVersionException handling that was introduced when IOException was
used to wrap RuntimeException.
Small fixes in netconf, more refactoring of exception handling will be needed there.

Maros Marsalek: Rebase commit + fix compliation issue in ShutdownTest

Change-Id: Iab89de6ef6ced0de0a267470f860912ae3c56892
Signed-off-by: Tomas Olvecky <tolvecky@cisco.com>
Signed-off-by: Maros Marsalek <mmarsale@cisco.com>
Merge "Modify config-api exceptions, bump config and netconf to 0.2.5-SNAPSHOT."