bitbake: Revert "fetch2/local.py: avoid using PREMIRROR"

This reverts commit e130dca85bac82bd4d88f94a6bf9fe36e8ad4d7c.

This is in fact a valid use case, for example the sstate.bbclass code
sets up SSTATE_MIRRORS as PREMIRRORS. Its quite common to map those
file:// urls to remote http:// urls and with the above change, this
no longer works.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/fetch2/local.py

@@ -126,8 +126,3 @@ class Local(FetchMethod):
     def clean(self, urldata, d):
         return
 
-    def try_premirror(self, urldata, d):
-        """
-        Should premirrors be used?
-        """
-        return False