veyron/services/mgmt/application/impl: fix error logic bug
veyron/services/mgmt/application/impl: fix error logic bug

The error returned by getACL was tested against ErrNotFound.ID without first
testing that err is non-nil. This would cause NewDispatcher to return a nil
dispatcher even when getACL returned no error (as happens when the server
already has a pre-existing store of acls, e.g. upon restart).

Change-Id: Ie91fa5298d727579410a7b1314c8affbf8bdfdd1

vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref