crosperf: fix a error.

_GetCacheDirForWrite was replaced by GetCacheDirForWrite
in result_cache.py, so this needs updated too.

BUG=none
TEST=it passes.

Change-Id: Ie3d63fbf2db2d3631644955cfa4bfda730099bdd
Reviewed-on: https://chrome-internal-review.googlesource.com/243468
Commit-Ready: Yunlian Jiang <yunlian@google.com>
Tested-by: Yunlian Jiang <yunlian@google.com>
Reviewed-by: Han Shen <shenhan@google.com>
1 file changed