Fix ImageAcquisitionDate parsing for DeltavisionReader

Previously, the last block of parseLogFile() was always escaped and the
creation date was being filled as a parameter/key value in the global
metadata. This commit restores the validity of the last block and fixes the
joda DATE_TIME pattern.
Merge pull request #1255 from sbesson/deltavision_acquisitiondate

Fix ImageAcquisitionDate parsing for DeltavisionReader