Remove std::ref in shm_event_loop

For some reason, this triggers a crash trace on the roboRIO, but on no
other processor.

Change-Id: I166cb6ead9b10933976250d46580beb1f75e417c
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/aos/events/shm_event_loop.cc b/aos/events/shm_event_loop.cc
index 3126265..2fbb445 100644
--- a/aos/events/shm_event_loop.cc
+++ b/aos/events/shm_event_loop.cc
@@ -159,7 +159,7 @@
     }
   }
 
-  bool FetchNext() { return FetchNextIf(std::ref(should_fetch_)); }
+  bool FetchNext() { return FetchNextIf(should_fetch_); }
 
   bool FetchNextIf(std::function<bool(const Context &)> fn) {
     const ipc_lib::LocklessQueueReader::Result read_result =
@@ -192,7 +192,7 @@
     return read_result == ipc_lib::LocklessQueueReader::Result::GOOD;
   }
 
-  bool Fetch() { return FetchIf(std::ref(should_fetch_)); }
+  bool Fetch() { return FetchIf(should_fetch_); }
 
   Context context() const { return context_; }