Add health@2.0::IHealthInfoBus/backup to system manifest.

This instance is provided by healthd when IHealthInfoBus/default
is not provided by vendor.

This entry cannot be removed (and healthd cannot be removed)
until all framework compatibility matrices "requires" health@2.0 HAL.

Bug: 62229583
Test: lshal
Test: no warning message for health HAL
Change-Id: Id7bd792fdf387ede859e1b6167d32f8da6311857
diff --git a/manifest.xml b/manifest.xml
index f34bfb1..417d7b1 100644
--- a/manifest.xml
+++ b/manifest.xml
@@ -89,6 +89,16 @@
           <instance>vr</instance>
       </interface>
     </hal>
+    <hal>
+        <name>android.hardware.health</name>
+        <transport>hwbinder</transport>
+        <version>2.0</version>
+        <interface>
+            <name>IHealth</name>
+            <!-- The backup instance provided by healthd. -->
+            <instance>backup</instance>
+        </interface>
+    </hal>
     <hal format="native">
         <name>netutils-wrapper</name>
         <!--