ID 279776 - It is no longer possible to remove a shortcut via Python in Mari

Problem summary
It is no longer possible to remove a shortcut via Python in Mari 

Customer reported version
3.3v1
Customer reported platform
windows10

Steps to reproduce

1) Evaluate the following in your Python Console:

2) This should located the shortcut
  showaction = mari.actions.find('/Mari/Geometry/Selection/Show All')

3) Next, print the shortcut to check it is set
print showaction.shortcut()

4) Remove the shortcut
showaction.removeShortcut()

5) If you are successful, Mari should return a traceback error when you attempt to print this again.
print showaction.shortcut()

6) In Mari 3.2v1 and 3.3v1, this does not seem to remove the shortcut

Workaround
You will need to remove shortcuts manually via the shortcuts preference editor.

Reproduced by support
Win 7 - 3.3v1, 3.2v1
OSX 10.12 - 3.3v1, 3.2v1
CentOS6 - 3.3v1, 3.2v1

Expected behaviour
Mari should remove the shortcut and return an error as it contains an empty value. It used to be possible to do this by using:
action.removeShortcut() or action.setShortcut('')

Actual behaviour
Mari continued to print the output of the shortcut as it was not removed.