Change the try/except/finally block to a try/finally block for python 2.4 compatibility.
Change the try/except/finally block to a try/finally block for python 2.4 compatibility.

Change-Id: I21fcbb761c168e2cbaeeae1c3850c97119f75cdd
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4735
Reviewed-by: Ishaan Joshi <d1d1e60202ec9f2503deb1b724986485a125d802@cloudera.com>
Tested-by: jenkins

cloudera/Impala,michaelhkw/incubator-impala,cloudera/Impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,cloudera/Impala,cloudera/Impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,cloudera/Impala,cloudera/Impala,michaelhkw/incubator-impala,cloudera/Impala,michaelhkw/incubator-impala