Suppress file deletion error message in FaultInjectionTestEnv (#6696)

Summary:
The error message is causing problems in the crash tests due to the
error parsing logic in db_crashtest.py.

This is a follow up PR for https://github.com/facebook/rocksdb/pull/6694.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6696

Test Plan: make check

Reviewed By: zhichao-cao

Differential Revision: D21021875

Pulled By: cheng-chang

fbshipit-source-id: 11e3f536df16941a89949ebcd2147cd8dfa3fbe0

test_util/fault_injection_test_env.cc

@@ -305,10 +305,6 @@ Status FaultInjectionTestEnv::DeleteFile(const std::string& f) {
     return GetError();
   }
   Status s = EnvWrapper::DeleteFile(f);
-  if (!s.ok()) {
-    fprintf(stderr, "Cannot delete file %s: %s\n", f.c_str(),
-            s.ToString().c_str());
-  }
   if (s.ok()) {
     UntrackFile(f);
   }