get_revision

Returns the revision of a data source.

This maps a particular version of a system-wide source to a user-specific source.

If doesn't match, the system-wide source will be copied to the user-specific evolution config directory, preserving the already present fields that are not defined by the system-wide source.

If it matches, no copying is done.

Parameters:

this	an SourceAutoconfig

Returns:

revision of the data source