Add logs in ProxyActivityStarter when it fails to launch an activity

Apparently, it doesn't log when it fails due to some reason.

In 369422714, we see it being started but the appwidget's config
 activity not being launched. The absorbed exception makes it harder to
  know. There isn't a system log as well.

  At least looking at logs, we think for some reason appwidget's
   configuration activity wasn't launched by launcher.

Bug: 369422714
Test: N/A logging
Flag: EXEMPT BUGFIX

Change-Id: I56294ef37d7ddceb61c4e6d0e10d0f24fde42cb2
1 file changed