Commit e26d61e introduced a bug that causes the error message "The
bridge you [sic!] looking for does not exist." if the bridge name
specified in the query ends on "Bridge"
(i.e. '&bridge=SoundcloudBridge'), while other queries work fine
(i.e. '&bridge=Soundcloud').
This commit fixes that issue by sanitizing the bridge name before
creating the class.
References #922