Revert "Convert WaitConditionHandle to use handle_signal"

This reverts commit a60f2722f8e084c4d68d2e439c6cc7c1d049b696.

This and/or the next commit (f2f2697c9d8f926869f93f34c0a6df0df7cba20a)
are causing Metadata to return blank after signals are processed.

Change-Id: Ic4e068fd1e26e51e826055cebed6a392a5595bf9
Partial-Bug: #1337772
Merge "Revert "Convert WaitConditionHandle to use handle_signal""