SDK: Fix missing min-tools-rev in platform source props

Change-Id: I4a70baa0d33e82b2b15e71ecf66285f3401a3735
diff --git a/sdk/platform_source.properties b/sdk/platform_source.properties
index 5e3ef13..947e3cc 100644
--- a/sdk/platform_source.properties
+++ b/sdk/platform_source.properties
@@ -6,3 +6,4 @@
 #AndroidVersion.CodeName=
 Layoutlib.Api=7
 Layoutlib.Revision=1
+Platform.MinToolsRev=14