git-svn: fix signed commit parsing

When parsing a commit object, git-svn wrongly think that a line containing spaces means the end of headers and the start of the commit message. In case of signed commit, the gpgsig entry contains a line with one space, so "git svn dcommit" will include part of the signature in the commit message. An example of such problem : http://svnweb.mageia.org/treasurer?view=revision&revision=86 This commit changes the regex to only match an empty line as separator between the headers and the commit message. Signed-off-by: Nicolas Vigier <boklm@mars-attacks.org> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Eric Wong <normalperson@yhbt.net>