Soleve issue of removing an optional document metadata
from a document that also contained existing required metadata.
Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>
Instead of inserting the path of the apps into the Python app,
the apps are now referenced by their full import path.
This solves name clashes with external or native Python libraries.
Example: Mayan statistics app vs. Python new statistics library.
Every app reference is now prepended with 'mayan.apps'.
Existing config.yml files need to be updated manually.
Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>
