Use a with statement.

chkcrontab_lib.py

@@ -14,6 +14,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# For Python 2.5
+from __future__ import with_statement
+
 """Processes crontab files and try to catch common errors.
 
 Parse crontab files and check each type of line for potential syntax errors.
@@ -1024,7 +1027,8 @@ def CheckCrontab(crontab_file, log):
 
   line_no = 0
   cron_line_factory = CronLineFactory()
-  for line in open(crontab_file, 'r'):
+  with open(crontab_file, 'r') as crontab_f:
+    for line in crontab_f:
       line = line.strip()
       line_no += 1