Don't return kPatchOatNeeded if there is no patch info.

Bug: 27693977
Change-Id: Ie1f27cc45f3cb434108a375136480cb92fd95e26
diff --git a/runtime/oat.cc b/runtime/oat.cc
index d13999a..80231f3 100644
--- a/runtime/oat.cc
+++ b/runtime/oat.cc
@@ -462,6 +462,10 @@
   return IsKeyEnabled(OatHeader::kPicKey);
 }
 
+bool OatHeader::HasPatchInfo() const {
+  return IsKeyEnabled(OatHeader::kHasPatchInfoKey);
+}
+
 bool OatHeader::IsDebuggable() const {
   return IsKeyEnabled(OatHeader::kDebuggableKey);
 }