[autotest] Fix a stale |_adb_run| invocation in |get_file|.

Fixing a missed |_adb_run| to |adb_run| conversion from previous commit
'6ea3e1c82.

BUG=chromium:548881
TEST=`test_that --board=$board $host network_WiFi_Reassociate`

Change-Id: I2e424965031b7b34bf9e9352d58cbfe7a72b1e18
Reviewed-on: https://chromium-review.googlesource.com/310266
Commit-Ready: Roshan Pius <rpius@chromium.org>
Tested-by: Roshan Pius <rpius@chromium.org>
Reviewed-by: Dan Shi <dshi@chromium.org>
1 file changed