Various build and test machines have multiple versions of java
installed and relying on the default "java" command being compatible
isn't practical (a machine may also build an older version of Impala
that might require a different java version). Since JAVA_HOME is already
required that can/should be used to determine which java binary to use.
This also includes a minor change to replace a block of code that was
using 4-space indent. Instead of using 2-space indent, that block was
replaced with one line.
Change-Id: I4b8698b2aa5411b5fa6c5bc06291625999478955
Reviewed-on: http://gerrit.cloudera.org:8080/310
Reviewed-by: Casey Ching <casey@cloudera.com>
Tested-by: Internal Jenkins
