[sources] Skip problematic sources when starting shell instead of crashing. Closes #3670208
At least this gives an opportunity to fix the problem in using c-c shell, which
is currently not possible because it crashes during initialization.
Notice that since sources are copy based, it should not be a problem at all to
have some disabled, beside for services such as authentication sources as
ldapfeed.
Document: cubicweb-doc
Title: CubicWeb documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/cubicweb-documentation/index.html
Files: /usr/share/doc/cubicweb-documentation/*.html