Key binding with F-# keys don't work anymore

[Adrien Pétremann]

1) Ubuntu version:
Ubuntu 14.04.2 LTS

2) Metacity version:
1:2.34.13-0ubuntu4.1

3) What you expected to happen:
Key binding on keys "F1" or "F2" etc.. should process the command bound on them.

4) What happened instead:
Pressing "F1" executes the application operation (often Help) instead of the system "F1" key binding

**Possible regression**
Everything worked fine with the version 1:2.34.13-0ubuntu4
This bug appeared with the update 1:2.34.13-0ubuntu4.1

**Note**
The key binding "F1" is mapped to "switch to workspace 1"
The key binding "F2" is mapped to "switch to workspace 2"
and so on.

Changing the binding to "<alt>+F1" makes the binding work again.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.