crate.py: use BPN instead of PN

If we don't use BPN then native packages will not extract correct since
PN will be something-native and we won't extract the something crate to
${S}.

lib/crate.py

@@ -180,7 +180,7 @@ class Crate(Wget):
         save_cwd = os.getcwd()
         os.chdir(rootdir)
 
-        pn = d.getVar('PN', True)
+        pn = d.getVar('BPN', True)
         if pn == ud.parm.get('name'):
             cmd = "tar -xz --no-same-owner -f %s" % thefile
         else: