import-tars: Add missing closing bracket

This fixes an obvious syntax error that snuck in commit 7e78795:

  syntax error at /home/ingmar/bin//git-import-tars line 143, near "/^$/ { "
  syntax error at /home/ingmar/bin//git-import-tars line 145, near "} else"
  syntax error at /home/ingmar/bin//git-import-tars line 152, near "}"

Signed-off-by: Ingmar Vanhassel <ingmar@exherbo.org>
Acked-and-Tested-by: Peter Krefting <peter@softwolves.pp.se>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/fast-import/import-tars.perl

@@ -140,7 +140,7 @@
 				} elsif (!$header_done && /^Author:\s+([^<>]*)\s+<(.*)>\s*$/i) {
 					$this_author_name = $1;
 					$this_author_email = $2;
-				} elsif (!$header_done && /^$/ { # empty line ends header.
+				} elsif (!$header_done && /^$/) { # empty line ends header.
 					$header_done = 1;
 				} else {
 					$commit_msg .= $_;