Fix a couple of type errors

One minor, one more significant spotted at:
#200 (comment)

Also rename reused `loader` variable to help avoid false positives.

python/phonenumbers/phonemetadata.py

@@ -328,14 +328,14 @@ def register_nongeo_region_loader(kls, country_code, loader):
     def load_all(kls):
         """Force immediate load of all metadata"""
         # Force expansion of contents to lists because we invalidate the iterator
-        for region_code, loader in list(kls._region_available.items()):
-            if loader is not None:  # pragma no cover
-                loader(region_code)
+        for region_code, region_loader in list(kls._region_available.items()):
+            if region_loader is not None:  # pragma no cover
+                region_loader(region_code)
                 kls._region_available[region_code] = None
-        for country_code, loader in list(kls._country_code_available.items()):
-            if loader is not None:
-                loader(country_code)
-                kls._country_code_available[region_code] = None
+        for country_code, cc_loader in list(kls._country_code_available.items()):
+            if cc_loader is not None:
+                cc_loader(country_code)
+                kls._country_code_available[country_code] = None
 
     @mutating_method
     def __init__(self,

python/phonenumbers/timezone.py

@@ -49,7 +49,7 @@
     if (os.path.basename(sys.argv[0]) == "buildmetadatafromxml.py" or
         os.path.basename(sys.argv[0]) == "buildprefixdata.py"):
         prnt("Failed to import generated data (but OK as during autogeneration)", file=sys.stderr)
-        TIMEZONE_DATA = {'4411': u('Europe/London')}
+        TIMEZONE_DATA = {'4411': (u('Europe/London'),)}
         TIMEZONE_LONGEST_PREFIX = 4
     else:
         raise