instaweb: fix unportable ';' usage in sed

Hint taken from Johannes.  I've tested this with sed --posix on
my system with GNU sed and it works fine with and also without
it.  Further portability testing/review would be good.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-instaweb.sh

@@ -194,9 +194,9 @@ EOF
 }
 
 script='
-s#^\(my\|our\) $projectroot =.*#\1 $projectroot = "'`dirname $fqgitdir`'";#;
-s#\(my\|our\) $gitbin =.*#\1 $gitbin = "'$GIT_EXEC_PATH'";#;
-s#\(my\|our\) $projects_list =.*#\1 $projects_list = $projectroot;#;
+s#^\(my\|our\) $projectroot =.*#\1 $projectroot = "'`dirname $fqgitdir`'";#
+s#\(my\|our\) $gitbin =.*#\1 $gitbin = "'$GIT_EXEC_PATH'";#
+s#\(my\|our\) $projects_list =.*#\1 $projects_list = $projectroot;#
 s#\(my\|our\) $git_temp =.*#\1 $git_temp = "'$fqgitdir/gitweb/tmp'";#'
 
 gitweb_cgi () {