bitbake: toastermain/settings: Avoid python filehandle closure warnings

Switch to using with blocks when accessing files to ensure file
descriptors are closed and avoid python warnings.

(Bitbake rev: e8574ee78eea23cc35900610bb15e47e40ef5ee1)

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

bitbake/lib/toaster/toastermain/settings.py

@@ -89,14 +89,17 @@ else:
                 from pytz.exceptions import UnknownTimeZoneError
                 try:
                     if pytz.timezone(zonename) is not None:
-                        zonefilelist[hashlib.md5(open(filepath, 'rb').read()).hexdigest()] = zonename
+                        with open(filepath, 'rb') as f:
+                            zonefilelist[hashlib.md5(f.read()).hexdigest()] = zonename
                 except UnknownTimeZoneError as ValueError:
                     # we expect timezone failures here, just move over
                     pass
             except ImportError:
-                zonefilelist[hashlib.md5(open(filepath, 'rb').read()).hexdigest()] = zonename
+                with open(filepath, 'rb') as f:
+                    zonefilelist[hashlib.md5(f.read()).hexdigest()] = zonename
 
-    TIME_ZONE = zonefilelist[hashlib.md5(open('/etc/localtime', 'rb').read()).hexdigest()]
+    with open('/etc/localtime', 'rb') as f:
+        TIME_ZONE = zonefilelist[hashlib.md5(f.read()).hexdigest()]
 
 # Language code for this installation. All choices can be found here:
 # http://www.i18nguy.com/unicode/language-identifiers.html