Use 0 based index for debug graph labels.

tabs/sensors.html

@@ -197,7 +197,7 @@
     </div>
     <div class="wrapper debug">
         <div class="plot_control">
-            <div class="title">Debug 1</div>
+            <div class="title">Debug 0</div>
             <dl>
                 <dt i18n="sensorsRefresh"></dt>
                 <dd class="rate">
@@ -225,7 +225,7 @@
         </svg>
         <div class="clear-both"></div>
         <div class="plot_control">
-            <div class="title">Debug 2</div>
+            <div class="title">Debug 1</div>
             <dl>
                 <dt>X:</dt><dd class="x">blue</dd>
             </dl>
@@ -239,7 +239,7 @@
         </svg>
         <div class="clear-both"></div>
         <div class="plot_control">
-            <div class="title">Debug 3</div>
+            <div class="title">Debug 2</div>
             <dl>
                 <dt>X:</dt><dd class="x">0</dd>
             </dl>
@@ -253,7 +253,7 @@
         </svg>
         <div class="clear-both"></div>
         <div class="plot_control">
-            <div class="title">Debug 4</div>
+            <div class="title">Debug 3</div>
             <dl>
                 <dt>X:</dt><dd class="x">0</dd>
             </dl>