fwk compat mat: health@2.0 is required

... on "current" compat mat level. They are kept optional
on upgrading devices.

Test: builds (assemble_vintf passes)
Bug: 63702641
Change-Id: Iafe64c4ffa7df8aa7f80a1b6cf599d56e7854f33
diff --git a/compatibility_matrix.current.xml b/compatibility_matrix.current.xml
index 940588f..4b09c3b 100644
--- a/compatibility_matrix.current.xml
+++ b/compatibility_matrix.current.xml
@@ -163,7 +163,7 @@
             <instance>default</instance>
         </interface>
     </hal>
-    <hal format="hidl" optional="true">
+    <hal format="hidl" optional="false">
         <name>android.hardware.health</name>
         <version>2.0</version>
         <interface>