sbcl: remove patch for ignoring contrib tests

Previously, contrib/sb-bsd-sockets wasn't working and so it would break the build.
This patch ignored that test failure and allowed the build to continue.
Since that module now builds, ignoring this test is no longer necessary.

srcpkgs/sbcl/patches/musl-fixes.patch

@@ -84,15 +84,6 @@
  ASFLAGS = $(CFLAGS)
  CPPFLAGS = -I. -DSBCL_PREFIX=\"$(SBCL_PREFIX)\"
  
---- make-target-contrib.sh	2016-11-30 08:07:35.000000000 +1100
-+++ make-target-contrib.sh	2016-12-17 15:57:51.934251451 +1100
-@@ -130,5 +130,5 @@
- done
- 
- if [ $HEADER_HAS_BEEN_PRINTED = true ]; then
--  exit 1
-+  exit 0
- fi
 --- contrib/sb-bsd-sockets/constants.lisp.orig
 +++ contrib/sb-bsd-sockets/constants.lisp
 @@ -93,8 +93,8 @@