Cannot open manifest: error -> warning

This is confusing devs as this is not an error yet and is expected
behavior.

Test: none
Change-Id: I67f04e88d19cb0f319915e4e9df97114e80caf75
diff --git a/base/HidlSupport.cpp b/base/HidlSupport.cpp
index 3b964f0..094e0b1 100644
--- a/base/HidlSupport.cpp
+++ b/base/HidlSupport.cpp
@@ -58,7 +58,7 @@
     const std::string package = fqName.package();
     const vintf::VendorManifest *vm = vintf::VendorManifest::Get();
     if (vm == nullptr) {
-        LOG(ERROR) << "getTransportFromManifest: Cannot find vendor interface manifest.";
+        LOG(WARNING) << "getTransportFromManifest: Cannot find vendor interface manifest.";
         return vintf::Transport::EMPTY;
     }
     size_t majorVer;