Don't use equals signs (=) in schema-ini descriptions

This is a translation-related problem. intltool extracts the strings in descriptions in schema-ini files only from the very last equals sign (=). Here is a real-world example:

_description=Orientation of Awn. (left=0, right=1, top=2 and bottom=3)

intltool extracts only this string: "3)"

So descriptions containing equals signs cannot be translated. The attached patch replaces them with "-", it was created with bzr diff.

There is also a corresponding Bug #587162 for awn-extras.