updated misused sass body-bg to container-bg variableon account and course views

lms/static/sass/course/base/_base.scss

@@ -35,7 +35,7 @@ a {
     width: 100%;
     border-radius: 3px;
     border: 1px solid $outer-border-color;
-    background: $body-bg;
+    background: $container-bg;
     @include box-shadow(0 1px 2px rgba(0, 0, 0, 0.05));
   }
 }
@@ -50,7 +50,7 @@ textarea,
 input[type="text"],
 input[type="email"],
 input[type="password"] {
-  background: $body-bg;
+  background: $white;
   border: 1px solid $border-color-2;
   @include border-radius(0);
   @include box-shadow(0 1px 0 0 rgba(255,255,255, 0.6), inset 0 0 3px 0 rgba(0,0,0, 0.1));

lms/static/sass/multicourse/_account.scss

@@ -6,7 +6,7 @@
 
 // page-level
 .view-register, .view-login, .view-passwordreset {
-  background: $body-bg;
+  background: $container-bg;
 
 
 
@@ -331,7 +331,7 @@
         }
 
         textarea, input {
-          background: $body-bg;
+          background: $container-bg;
           color: rgba(0,0,0,.25);
         }
       }