use more convenient iter() method for processing lines in files

hours

@@ -45,10 +45,7 @@ def get_adjustments():
     if not os.path.isfile(ADJUSTMENTS_FILE):
         return adjustments
     f = open(ADJUSTMENTS_FILE, 'r')
-    while True:
-        line = f.readline()
-        if line == '':
-            break
+    for line in iter(f.readline, ''):
         m = re.match(r'adj\s+(\S+)\s+(\S+)', line)
         if m is not None:
             adjustments[m.group(1)] = float(m.group(2))
@@ -113,10 +110,7 @@ def main(argv):
         times.append([None, None])
 
     f = open(LOG_FILE, 'r')
-    while True:
-        line = f.readline()
-        if line == '':
-            break
+    for line in iter(f.readline, ''):
         if (re.search(r'gnome-screensaver.*unlocked.login.keyring', line)
                 or re.search(r'screen unlocked', line)):
             # found a login line