Before this change, when resolving full connector path, all errors were
ignored. As a result, when the connector was installed but not
correctly built (e.g. loopback-connector-db2 which uses a native addon),
a very confusing message was reported by LoopBack.
In this commit, I am fixing the code handling `require()` errors
to ignore only MODULE_NOT_FOUND errors that contain the name
of the required module.
Miroslav Bajtoš
Amir Jafarian
Ryan Graham