liblog: disable header_abi_checker

I'm about to make a bunch of changes that are safe for backwards
compatibility, but would otherwise flag the checker, so it's time to
temporarily disable it.

Test: CLs pass despite making header changes
Change-Id: Ibc2d4ae51fb8e6125b9117ccd92bf821db945e67

liblog/Android.bp

@@ -105,6 +105,11 @@ cc_library {
         versions: ["10000"],
     },
 
+    // TODO(tomcherry): Renable this before release branch is cut
+    header_abi_checker: {
+        enabled: false,
+    },
+
     cflags: [
         "-Wall",
         "-Werror",