base-files: remove remaining uses of %N, and drop VERSION_NICK config symbol

Fixes d23e1e1e1a "merge: properly remove %n / %N references"

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

package/base-files/files/usr/lib/os-release

@@ -1,8 +1,8 @@
 NAME="%D"
-VERSION="%V, %N"
+VERSION="%V"
 ID="%d"
 ID_LIKE="lede openwrt"
-PRETTY_NAME="%D %N %V"
+PRETTY_NAME="%D %V"
 VERSION_ID="%v"
 HOME_URL="%m"
 BUG_URL="%b"
@@ -15,4 +15,4 @@ LEDE_DEVICE_MANUFACTURER="%M"
 LEDE_DEVICE_MANUFACTURER_URL="%m"
 LEDE_DEVICE_PRODUCT="%P"
 LEDE_DEVICE_REVISION="%h"
-LEDE_RELEASE="%D %N %V %C"
+LEDE_RELEASE="%D %V %C"

package/base-files/image-config.in

@@ -163,13 +163,6 @@ if VERSIONOPT
 			This is the name of the release distribution.
 			If unspecified, it defaults to OpenWrt.
 
-	config VERSION_NICK
-		string
-		prompt "Release version nickname"
-		help
-			This is the release codename embedded in the image.
-			If unspecified, it defaults to the name of source branch.
-
 	config VERSION_NUMBER
 		string
 		prompt "Release version number"