Turn OmahaRequestPrepAction into OmahaRequestDeviceParams.

SConstruct

Index: SConstruct
diff --git a/SConstruct b/SConstruct
index df29f868731e452bef2308ec9ea0256d2079850d..c3960bdcce055de287214dad97b45aa501b5e94d 100644
--- a/SConstruct
+++ b/SConstruct
@@ -210,7 +210,7 @@ sources = Split("""action_processor.cc
                    marshal.glibmarshal.c
                    omaha_hash_calculator.cc
                    omaha_request_action.cc
-                   omaha_request_prep_action.cc
+                   omaha_request_params.cc
                    omaha_response_handler_action.cc
                    postinstall_runner_action.cc
                    set_bootable_flag_action.cc
@@ -243,7 +243,7 @@ unittest_sources = Split("""action_unittest.cc
                             mock_http_fetcher.cc
                             omaha_hash_calculator_unittest.cc
                             omaha_request_action_unittest.cc
-                            omaha_request_prep_action_unittest.cc
+                            omaha_request_params_unittest.cc
                             omaha_response_handler_action_unittest.cc
                             postinstall_runner_action_unittest.cc
                             set_bootable_flag_action_unittest.cc