NSD file referred by DependsOn may not be present

In NSDImpl.java, findXXX() use refersToNS() provided by DependsOn without checking that it is present (the file containing the requested NS may not be loaded), thus NPE.

mentioned in merge request !10 (merged)

By Dominique Marcadet on 2019-02-14T09:45:24 (imported from GitLab project)

created merge request !10 (merged) to address this issue

By Dominique Marcadet on 2019-02-14T09:45:24 (imported from GitLab project)

closed via merge request !10 (merged)

By Dominique Marcadet on 2019-02-14T09:56:01 (imported from GitLab project)

mentioned in commit 315be011

By Dominique Marcadet on 2019-02-14T09:56:01 (imported from GitLab project)