Fix rename

We shouldn't be leaving a copy of the original filename laying around.
This fixes one of a few broken savedata checks in DRAGON BALL XENOVERSE (CUSA01341)

src/core/libraries/kernel/file_system.cpp

@@ -751,6 +751,7 @@ s32 PS4_SYSV_ABI posix_rename(const char* from, const char* to) {
         return -1;
     }
     std::filesystem::copy(src_path, dst_path, std::filesystem::copy_options::overwrite_existing);
+    std::filesystem::remove(src_path);
     return ORBIS_OK;
 }