site.mk: advance default version to post-0.5.1

site.mk

@@ -22,7 +22,7 @@ GLUON_SITE_PACKAGES := \
 	iptables \
 	haveged
 
-DEFAULT_GLUON_RELEASE := 0.5+0-exp$(shell date '+%Y%m%d')
+DEFAULT_GLUON_RELEASE := 0.5.1+exp$(shell date '+%Y%m%d')
 DEFAULT_GLUON_PRIORITY := 0
 
 GLUON_RELEASE ?= $(DEFAULT_GLUON_RELEASE)