.: remove trailing white spaces

blame tibor this one ;-)
```
find . -type f -not -name '*.png' -not -name '*.go' -not -name '*.md'
-not -name '*.tar' -not -name '*.pem' -not -path './vendor/*' -not -path
'./.git/*' -not -path '*/testdata/*' -not -path './docs/*images*' -not
-path '*/testfiles/*' -not -path './bundles/*' -not -path
'./docs/*static*/*' -not -path './docs/*article-img/*' -exec grep -HnEl
'[[:space:]]$' {} \; | xargs sed -iE 's/[[:space:]]*$//'
```

Signed-off-by: Vincent Batts <vbatts@redhat.com>

contrib/completion/bash/docker

@@ -22,7 +22,7 @@
 # must have access to the socket for the completions to function correctly
 #
 # Note for developers:
-# Please arrange options sorted alphabetically by long name with the short 
+# Please arrange options sorted alphabetically by long name with the short
 # options immediately following their corresponding long form.
 # This order should be applied to lists, alternatives and code blocks.
 
@@ -257,8 +257,8 @@ _docker_build() {
 			;;
 		--file|-f)
 			_filedir
-			return	
-			;;	
+			return
+			;;
 	esac
 
 	case "$cur" in