Clean up headers

Updates headers to match style guide and makes them consistent
throughout pages in the GUI. Removes instances where a header
element existed and a different header style was being applied.
For example, <h2 class="h4">

Tested: Ran GUI locally and verified that headers look consistent
and have the appropriate sizing while using Chrome, Firefox and
Safari.

Change-Id: I187136298ed2bfd36c40c2b80d5a4f20947cbe56
Signed-off-by: beccabroek <beccabroek@gmail.com>
diff --git a/app/server-control/controllers/power-operations-controller.html b/app/server-control/controllers/power-operations-controller.html
index b32792a..3dc69d2 100644
--- a/app/server-control/controllers/power-operations-controller.html
+++ b/app/server-control/controllers/power-operations-controller.html
@@ -3,7 +3,7 @@
     <div class="row column">
         <h1>Server power operations</h1>
         <div class="power__current-status page-header">
-            <h2 class="inline h4">Current status</h2>
+            <h2 class="inline">Current status</h2>
             <div class="power__status-log inline float-right">Last power operation at <span class="courier-bold">{{power_time | localeDate}}</span></div>
         </div>
     </div>
@@ -15,7 +15,7 @@
     </div>
     <div class="row column">
         <div class="row column">
-            <h3 class="h4 subhead">Select a power operation</h3>
+            <h3 class="subhead">Select a power operation</h3>
         </div>
         <span class="inactive-message" ng-show="dataService.server_state == 'Unreachable'">There are no power operations to display while a power operation is in progress. When complete, any new power operations will be displayed here.</span>
         <!-- Power on displays only when server is shutdown -->