rust: drop unnecessary patch

Not sure what version this patch appears to have become unnecessary but
I verified it by checking the output in
build/tmp/sstate-control/manifest-x86_64-rust-native.populate_sysroot
and the installed files and their paths didn't change with and without
this patch.

Signed-off-by: Doug Goldstein <cardoe@cardoe.com>

recipes-devtools/rust/files/rust-1.12.1/0003-mk-add-missing-CFG_LIBDIR_RELATIVE.patch

@@ -1,27 +0,0 @@
-From 128503bf447e82b9e99bea8ef83294a6446036b5 Mon Sep 17 00:00:00 2001
-From: Cody P Schafer <dev@codyps.com>
-Date: Tue, 18 Nov 2014 13:48:14 -0500
-Subject: [PATCH 03/10] mk: add missing CFG_LIBDIR_RELATIVE
-
----
- mk/grammar.mk | 4 ++--
- 1 file changed, 2 insertions(+), 2 deletions(-)
-
-diff --git a/mk/grammar.mk b/mk/grammar.mk
-index 0d527bd..926f247 100644
---- a/mk/grammar.mk
-+++ b/mk/grammar.mk
-@@ -11,8 +11,8 @@
- BG = $(CFG_BUILD_DIR)/grammar/
- SG = $(S)src/grammar/
- B = $(CFG_BUILD_DIR)/$(CFG_BUILD)/stage2/
--L = $(B)lib/rustlib/$(CFG_BUILD)/lib
--LD = $(CFG_BUILD)/stage2/lib/rustlib/$(CFG_BUILD)/lib/
-+L = $(B)$(CFG_LIBDIR_RELATIVE)/rustlib/$(CFG_BUILD)/lib
-+LD = $(CFG_BUILD)/stage2/$(CFG_LIBDIR_RELATIVE)/rustlib/$(CFG_BUILD)/lib/
- RUSTC = $(STAGE2_T_$(CFG_BUILD)_H_$(CFG_BUILD))
- ifeq ($(CFG_OSTYPE),apple-darwin)
- 	FLEX_LDFLAGS=-ll
--- 
-2.10.0
-