Historian: Fixed date format in header block.
Historian: Fixed date format in header block.

git-tfs-id: [https://tfs.codeplex.com/tfs/TFS07]$/openpdc/Contributor Resources;C29754

GridProtectionAlliance/gsf,GridProtectionAlliance/gsf,rmc00/gsf,GridProtectionAlliance/gsf,GridProtectionAlliance/gsf,GridProtectionAlliance/gsf,rmc00/gsf,GridProtectionAlliance/gsf,rmc00/gsf,rmc00/gsf,rmc00/gsf,rmc00/gsf,rmc00/gsf,GridProtectionAlliance/gsf,GridProtectionAlliance/gsf