Explicitly set elevation on ActionBarTabTextStyle

The default elevation appears to have changed in the
framework. So we need to explicitly set the value to 0dp.

Bug: 19589425
Change-Id: Ic58a14ba98be59d47204df155968c13bd3c7902f
diff --git a/res/values/styles.xml b/res/values/styles.xml
index d4826a1..ca3f450 100644
--- a/res/values/styles.xml
+++ b/res/values/styles.xml
@@ -163,6 +163,7 @@
         <item name="android:textColor">@color/tab_text_color</item>
         <item name="android:textSize">@dimen/tab_text_size</item>
         <item name="android:fontFamily">@string/tab_font_family</item>
+        <item name="android:elevation">0dp</item>
         <item name="android:textStyle">bold</item>
     </style>