BUG-981: harden exception handling

This patch hardens the RuntimeGeneratedMappingServiceImpl error handling
by eliminating the use of sneakyThrow and properly chaining/logging
error causes.

Change-Id: Ia974c8cce3aab8c0f12dd318e4168932a025bb07
Signed-off-by: Robert Varga <rovarga@cisco.com>
(cherry picked from commit 5ff2abeff78e84557316416aa4d255226ffa048e)
Signed-off-by: Robert Varga <rovarga@cisco.com>
Merge "BUG-981: harden exception handling" into stable/hydrogen