Regenerate soong's build.ninja.in

This was causing us to rerun minibootstrap every build.

Bug: 63720725
Test: m -j nothing; m -j nothing
Change-Id: Iedd18b54d34f3f20580d0522a4a7d9c5f216caaa
diff --git a/build.ninja.in b/build.ninja.in
index 9449d73..8aa0f76 100644
--- a/build.ninja.in
+++ b/build.ninja.in
@@ -556,7 +556,7 @@
 build ${g.bootstrap.buildDir}/.minibootstrap/build.ninja.in: $
         g.bootstrap.build.ninja ${g.bootstrap.srcDir}/Android.bp | ${builder}
     builder = ${g.bootstrap.BinDir}/minibp
-    extra =  -t
+    extra = $ -t
 default ${g.bootstrap.buildDir}/.minibootstrap/build.ninja.in
 
 build ${g.bootstrap.buildDir}/.minibootstrap/build.ninja: $