core: Fix ConfigValues.UknownTaskPrePollingLapse name

Renames ConfigValues attribute UknownTaskPrePollingLapse
to UnknownTaskPrePollingLapse.

Change-Id: I4cc27adb41d31a11a8c365934e730826552a29b8
Bug-Url: https://bugzilla.redhat.com/1112036
Signed-off-by: Martin Perina <mperina@redhat.com>