Follow argument changes to RuleBuilder

Pass pctx and ctx to NewRuleBuilder instead of RuleBuilder.Build,
and don't pass ctx to RuleBuilderCommand.BuiltTool.  Follows the
changes in I63e6597e19167393876dc2259d6f521363b7dabc.

Test: m checkbuild
Change-Id: I5d11e07ae1a24a967e379c151f4f5d7d188c6cc0
diff --git a/tools/fs_config/fs_config.go b/tools/fs_config/fs_config.go
index 16bcefa..4c324fb 100644
--- a/tools/fs_config/fs_config.go
+++ b/tools/fs_config/fs_config.go
@@ -48,10 +48,10 @@
 		path := android.PathForModuleGen(ctx, "empty")
 		t.paths = android.Paths{path}
 
-		rule := android.NewRuleBuilder()
+		rule := android.NewRuleBuilder(pctx, ctx)
 		rule.Command().Text("rm -rf").Output(path)
 		rule.Command().Text("touch").Output(path)
-		rule.Build(pctx, ctx, "fs_config_empty", "create empty file")
+		rule.Build("fs_config_empty", "create empty file")
 	}
 }