Merge pull request zendframework/zendframework#3139 branch 'hotfix/ad…

…d-detail-to-exception-message'

src/ServiceManager.php

@@ -630,7 +630,11 @@ public function setAlias($alias, $nameOrAlias)
         }
 
         if ($this->allowOverride === false && $this->has(array($cAlias, $alias), false)) {
-            throw new Exception\InvalidServiceNameException('An alias by this name already exists');
+            throw new Exception\InvalidServiceNameException(sprintf(
+                'An alias by the name "%s" or "%s" already exists',
+                $cAlias,
+                $alias
+            ));
         }
 
         $this->aliases[$cAlias] = $nameOrAlias;