vergen: use git-log --pretty=email instead of git-log --pretty=format:"%b"
vergen: use git-log --pretty=email instead of git-log --pretty=format:"%b"

The former works with older git versions, too and provides us with
basically the same information ...


git-svn-id: de0f43fde411c0742886ef3f23a5bd305369a36f@1258 95d9436f-6502-0410-902c-bd9569d1a17e

stefanomarty/openxpki,oliwel/openxpki,oliwel/openxpki,mrscotty/openxpki,openxpki/openxpki,aleibl/openxpki,oliwel/openxpki,aleibl/openxpki,stefanomarty/openxpki,mrscotty/openxpki,stefanomarty/openxpki,aleibl/openxpki,aleibl/openxpki,aleibl/openxpki,oliwel/openxpki,stefanomarty/openxpki,oliwel/openxpki,mrscotty/openxpki,openxpki/openxpki,stefanomarty/openxpki,stefanomarty/openxpki,aleibl/openxpki,openxpki/openxpki,oliwel/openxpki,openxpki/openxpki