Save update_engine.log before printing it
Otherwise we'd keep getting the following error:
```
WARNING : Update failed. Dumping update_engine.log for debugging and/or
bug reporting.
tail: cannot open
/b/c/cbuild/repository/chroot/tmp/cbuildbotoi3IrH/pfq_suite/test_harness/all/SimpleTestUpdateAndVerify/1_update/update_engine.log
for reading: No such file or directory
```
BUG=None
TEST=cros_vm_update includes the update_engine from the test VM in the
final update.log
Change-Id: I7f9b143f2c5c69456555191bf8c699674dd7ffad
Reviewed-on: https://chromium-review.googlesource.com/622221
Commit-Ready: Daniel Wang <wonderfly@google.com>
Tested-by: Daniel Wang <wonderfly@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed
