Fixing error checking of PathService::Get.

The return value of PathService::Get was being checked with the FAILED()
macro which is intended for use with HRESULT return types. Because
PathService::Get returns a bool and FAILED treats all non-negative
numbers as success, failures will never be detected.

This was found by VC++'s /analyze which said:
src\cloud_print\virtual_driver\win\install\setup.cc(510) : warning C6215:
Cast between semantically different integer types:  a Boolean type to
HRESULT.

The original bug was introduced
by https://chromiumcodereview.appspot.com/11876005

BUG=427616

Review URL: https://codereview.chromium.org/740463006

Cr-Commit-Position: refs/heads/master@{#307280}

cloud_print/virtual_driver/win/install/setup.cc

@@ -507,7 +507,7 @@ HRESULT ExecuteCommands() {
       *base::CommandLine::ForCurrentProcess();
 
   base::FilePath exe_path;
-  if (FAILED(PathService::Get(base::DIR_EXE, &exe_path)) ||
+  if (!PathService::Get(base::DIR_EXE, &exe_path) ||
       !base::DirectoryExists(exe_path)) {
     return HRESULT_FROM_WIN32(ERROR_PATH_NOT_FOUND);
   }