Disallow underscores in plan names

Plan names are included in the node hostnames created during
deployment. However underscores are not actually allowed in hostnames,
and having them there can cause issues down the line.

Change-Id: Ie8b9376e53a14b857836d90331ff32e5189d1574
Partial-Bug: #1644587
(cherry picked from commit 1a737d0794)

src/js/components/plan/PlanFormTabs.js

@@ -52,9 +52,9 @@ class PlanFormTab extends React.Component {
                          inputColumnClasses="col-sm-7"
                          labelColumnClasses="col-sm-3"
                          placeholder="Add a Plan Name"
-                         validations={{matchRegexp: /^[A-Za-z0-9_-]+$/}}
+                         validations={{matchRegexp: /^[A-Za-z0-9-]+$/}}
                          validationError="Please use only alphanumeric characters and
-                                          - or _"
+                                          -"
                          required />
         <PlanUploadTypeRadios title="Upload Type"
                               inputColumnClasses="col-sm-7"