format-patch --attach: not folding some long headers.

Panagiotis Issaris reports that some MUAs seem not to like
folded "content-type" and "content-disposition" headers, so this
makes format-patch --attach output to avoid them.

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/log-tree.c b/log-tree.c
index 7b3ad7d..8797aa1 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -186,7 +186,7 @@
 			snprintf(subject_buffer, sizeof(subject_buffer) - 1,
 				 "%s"
 				 "MIME-Version: 1.0\n"
-				 "Content-Type: multipart/mixed;\n"
+				 "Content-Type: multipart/mixed;"
 				 " boundary=\"%s%s\"\n"
 				 "\n"
 				 "This is a multi-part message in MIME "
@@ -202,10 +202,10 @@
 
 			snprintf(buffer, sizeof(buffer) - 1,
 				 "--%s%s\n"
-				 "Content-Type: text/x-patch;\n"
+				 "Content-Type: text/x-patch;"
 				 " name=\"%s.diff\"\n"
 				 "Content-Transfer-Encoding: 8bit\n"
-				 "Content-Disposition: %s;\n"
+				 "Content-Disposition: %s;"
 				 " filename=\"%s.diff\"\n\n",
 				 mime_boundary_leader, opt->mime_boundary,
 				 sha1,