Fix test_udfs.py test_udf_invalid_symbol location
Fix test_udfs.py test_udf_invalid_symbol location

We need to use paths that prepend $FILESYSTEM_PREFIX
so that paths are qualified when running the tests against the
non-default filesystem (e.g. S3).

Change-Id: I40b23d550aef67fcc5ebeb4640ed626d4d6361f8
Reviewed-on: http://gerrit.cloudera.org:8080/201
Reviewed-by: Dan Hecht <20ebd99959f0f6e5dcb0fc319b4d8ef53a16b5fb@cloudera.com>
Tested-by: Internal Jenkins

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