build: use SNAPSHOT instead of CURRENT to designate untagged branch builds

Calling a build ##.##-CURRENT might mislead users into thinking that this
build is the most current release of a branch.
Signed-off-by: NJo-Philipp Wich <jo@mein.io>

include/version.mk

@@ -31,7 +31,7 @@ qstrip_escape=$(subst ','\'',$(call qstrip,$(1)))
 sanitize = $(call tolower,$(subst _,-,$(subst $(space),-,$(1))))
 
 VERSION_NUMBER:=$(call qstrip_escape,$(CONFIG_VERSION_NUMBER))
-VERSION_NUMBER:=$(if $(VERSION_NUMBER),$(VERSION_NUMBER),CURRENT)
+VERSION_NUMBER:=$(if $(VERSION_NUMBER),$(VERSION_NUMBER),SNAPSHOT)
 
 VERSION_CODE:=$(call qstrip_escape,$(CONFIG_VERSION_CODE))
 VERSION_CODE:=$(if $(VERSION_CODE),$(VERSION_CODE),$(REVISION))

package/base-files/image-config.in

@@ -175,8 +175,8 @@ if VERSIONOPT
 		prompt "Release version number"
 		help
 			This is the release version number embedded in the image.
-			If unspecified, it defaults to CURRENT for the master branch
-			or to ##.##-CURRENT on release branches.
+			If unspecified, it defaults to SNAPSHOT for the master branch
+			or to ##.##-SNAPSHOT on release branches.
 
 	config VERSION_CODE
 		string
@@ -195,8 +195,8 @@ if VERSIONOPT
 			This is the repository address embedded in the image, it defaults
 			to the trunk snapshot repo; the url may contain the following placeholders:
 			 %R .. Repository revision ID
-			 %V .. Configured release version number or "CURRENT", uppercase
-			 %v .. Configured release version number or "current", lowercase
+			 %V .. Configured release version number or "SNAPSHOT", uppercase
+			 %v .. Configured release version number or "snapshot", lowercase
 			 %C .. Configured release revision code or value of %R, uppercase
 			 %c .. Configured release revision code or value of %R, lowercase
 			 %N .. Release name, uppercase