kbuild: mkcompile_h: do not create .version

This script does not need to create .version; it will be created by
scripts/link-vmlinux.sh later.  Clean-up the code slightly.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

scripts/mkcompile_h

@@ -27,12 +27,7 @@ LC_ALL=C
 export LC_ALL
 
 if [ -z "$KBUILD_BUILD_VERSION" ]; then
-	if [ -r .version ]; then
-		VERSION=`cat .version`
-	else
-		VERSION=0
-		echo 0 > .version
-	fi
+	VERSION=$(cat .version 2>/dev/null || echo 1)
 else
 	VERSION=$KBUILD_BUILD_VERSION
 fi