more generalisation of commonly used code constructs

include/hubloc.php

@@ -266,25 +266,11 @@ function hubloc_mark_as_down($posturl) {
 
 function locations_by_netid($netid) {
 
-	$strloc = '';
-
 	$locs = q("select hubloc_addr as location from hubloc left join site on hubloc_url = site_url where hubloc_hash = '%s' and hubloc_deleted = 0 and site_dead = 0",
 		dbesc($netid)
 	);
 
-	if($locs) {
-		foreach($locs as $l) {
-			if(!($l['location']))
-				continue;
-			if(strpos($strloc,$l['location']) !== false)
-				continue;
-			if(strlen($strloc))
-				$strloc .= ', ';
-			$strloc .= $l['location'];
-		}
-	}
-
-	return $strloc;	
+	return array_elm_to_str($locs,'location',', ');
 
 }