BUILD: scripts: automatically update the branch in version.h when releasing

The stats page proudly displays "Updates (v1.5)". This version is inherited
from version.h which has not been updated since 1.5, so let's teach the
create-release script about it.

This must be backported to 1.7. 1.6 now uses the same script (externally)
for the release and will automatically benefit from it.
diff --git a/scripts/create-release b/scripts/create-release
index 35688f0..21649c9 100755
--- a/scripts/create-release
+++ b/scripts/create-release
@@ -192,6 +192,10 @@
 sed -e "s:Copyright 2000-[0-9]*\s*Willy Tarreau.*>:Copyright 2000-$YEAR Willy Tarreau <willy@haproxy.org>:" \
     -i src/haproxy.c
 
+echo "Updating version.h ..."
+sed -e "s:^\(#define\s*PRODUCT_BRANCH\s*\)\"[^\"]*\":\1\"$BRANCH\":" \
+    -i include/common/version.h
+
 if [ -n "$INTERACTIVE" ]; then
 	vi CHANGELOG VERSION VERDATE examples/haproxy*.spec \
 	   src/haproxy.c README doc/configuration.txt \