minor style change to keep videos from blowing out in verification

lms/static/sass/views/_verification.scss

@@ -50,8 +50,6 @@ body.register.verification {
 
 
 
-
-
   .progress {
 
     .progress-step {
@@ -163,4 +161,9 @@ body.register.verification {
   }
 
 
+  video {
+    width: 512px;
+    height: 384px;
+  }
+
 }