Correct a minor grammar error. (docker#3917)

normanhh3 · johndmulhausen · commit b68696b78962 · 2017-07-18T18:52:30.000-07:00
Saw a grammar correction I couldn't help but correct.
diff --git a/swarm/plan-for-production.md b/swarm/plan-for-production.md
@@ -103,7 +103,7 @@ securely configure your network.
 
 All production environments should be highly available, meaning they are
 continuously operational over long periods of time. To achieve high
-availability, an environment must the survive failures of its individual
+availability, an environment must survive failures of its individual
 component parts.
 
 The following sections discuss some technologies and best practices that can
