Move ocf_request from utils

ocf_request has always been first class citizen in OCF,
so lets place it along with another essential objects.

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>

src/utils/utils_pipeline.c

@@ -1,8 +1,8 @@
 #include "ocf/ocf.h"
 #include "../engine/cache_engine.h"
 #include "../engine/engine_common.h"
+#include "../ocf_request.h"
 #include "utils_pipeline.h"
-#include "utils_req.h"
 
 struct ocf_pipeline {
 	struct ocf_pipeline_properties *properties;