[BUGFIX] Do not translate L10N with fallback

Change-Id: I23633ccfed6c55c6028f6497457a0e6bbfc3c01b
(bug 57879): raise the right form for isRedirectPage exception

I am confused: This form is a deprecated form of raising exception (W602)
whereas raise IsRedirectPage(self._redirarg) does not work.

Change-Id: I1263af62e109688cc3ad28b2f1fad525d4766930
Merge changes I1263af62,I23633ccf

* changes:
  (bug 57879): raise the right form for isRedirectPage exception
  [BUGFIX] Do not translate L10N with fallback