fix BusyBox sed

BusyBox sed works the same way as GNU sed

Author: tipok

staging/src/k8s.io/kubectl/pkg/cmd/completion/completion.go

@@ -275,7 +275,7 @@ autoload -U +X bashcompinit && bashcompinit
 # use word boundary patterns for BSD or GNU sed
 LWORD='[[:<:]]'
 RWORD='[[:>:]]'
-if sed --help 2>&1 | grep -q GNU; then
+if sed --help 2>&1 | grep -q 'GNU\|BusyBox'; then
 	LWORD='\<'
 	RWORD='\>'
 fi