Change findbugs modifications from presubmit error->warning

build/android/PRESUBMIT.py

Index: build/android/PRESUBMIT.py
diff --git a/build/android/PRESUBMIT.py b/build/android/PRESUBMIT.py
index fceeec3eab6e7876b7b3e14c1a096b292e780c81..2751f4a394ef63d74f9c962b72dee3700c8e89e3 100644
--- a/build/android/PRESUBMIT.py
+++ b/build/android/PRESUBMIT.py
@@ -16,15 +16,15 @@ _DELETIONS_ONLY_FILES = (
 def _CheckDeletionsOnlyFiles(input_api, output_api):
   """Check that a certain listed files only have deletions.
   """
-  errors = []
+  warnings = []
   for f in input_api.AffectedFiles():
     if f.LocalPath() in _DELETIONS_ONLY_FILES:
       if f.ChangedContents():
-        errors.append(f.LocalPath())
+        warnings.append(f.LocalPath())
   results = []
-  if errors:
-    results.append(output_api.PresubmitError(
-        'Following files should only contain deletions.', errors))
+  if warnings:
+    results.append(output_api.PresubmitPromptWarning(
+        'Following files should only contain deletions.', warnings))
   return results