Remove easy uses of //aos/mutex

I was hoping to get rid of it completely as one of the nontrivial users
of AOS_LOG, but need to write a compatible condition variable first.

Change-Id: I86c1c4084882bf789baabd0255e115d821154830
diff --git a/y2017/BUILD b/y2017/BUILD
index ca3e221..3c1fe21 100644
--- a/y2017/BUILD
+++ b/y2017/BUILD
@@ -12,8 +12,8 @@
     visibility = ["//visibility:public"],
     deps = [
         "//aos/logging",
-        "//aos/mutex",
         "//aos/network:team_number",
+        "//aos/stl_mutex",
         "//frc971:constants",
         "//frc971/shooter_interpolation:interpolation",
         "//y2017/control_loops/drivetrain:polydrivetrain_plants",