glibc: Drop nss-skip-unavail.patch

From a quick look at the 1063-line monstrosity that is gaih_inet(), I
*think* that this patch is no longer needed.  But I could be wrong.

pkgs/development/libraries/glibc/2.17/common.nix

@@ -32,30 +32,7 @@ stdenv.mkDerivation ({
   enableParallelBuilding = true;
 
   patches =
-    [ /* Fix for NIXPKGS-79: when doing host name lookups, when
+    [ /* Have rpcgen(1) look for cpp(1) in $PATH.  */
-         nsswitch.conf contains a line like
-
-           hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4
-
-         don't return an error when mdns4_minimal can't be found.  This
-         is a bug in Glibc: when a service can't be found, NSS should
-         continue to the next service unless "UNAVAIL=return" is set.
-         ("NOTFOUND=return" refers to the service returning a NOTFOUND
-         error, not the service itself not being found.)  The reason is
-         that the "status" variable (while initialised to UNAVAIL) is
-         outside of the loop that iterates over the services, the
-         "files" service sets status to NOTFOUND.  So when the call to
-         find "mdns4_minimal" fails, "status" will still be NOTFOUND,
-         and it will return instead of continuing to "dns".  Thus, the
-         line
-
-           hosts: mdns4_minimal [NOTFOUND=return] dns mdns4
-
-         does work because "status" will contain UNAVAIL after the
-         failure to find mdns4_minimal. */
-      ./nss-skip-unavail.patch
-
-      /* Have rpcgen(1) look for cpp(1) in $PATH.  */
       ./rpcgen-path.patch
 
       /* Allow NixOS and Nix to handle the locale-archive. */

pkgs/development/libraries/glibc/2.17/nss-skip-unavail.patch

@@ -1,21 +0,0 @@
-diff -ru glibc-2.11.2-orig/sysdeps/posix/getaddrinfo.c glibc-2.11.2/sysdeps/posix/getaddrinfo.c
---- glibc-2.11.2-orig/sysdeps/posix/getaddrinfo.c	2010-05-19 22:38:20.000000000 +0200
-+++ glibc-2.11.2/sysdeps/posix/getaddrinfo.c	2010-08-05 18:39:54.259556327 +0200
-@@ -505,8 +505,6 @@
- 	  int no_data = 0;
- 	  int no_inet6_data = 0;
- 	  service_user *nip = NULL;
--	  enum nss_status inet6_status = NSS_STATUS_UNAVAIL;
--	  enum nss_status status = NSS_STATUS_UNAVAIL;
- 	  int no_more;
- 	  int old_res_options;
- 
-@@ -702,6 +700,8 @@
- 
- 	  while (!no_more)
- 	    {
-+ 	      enum nss_status inet6_status = NSS_STATUS_UNAVAIL;
-+ 	      enum nss_status status = NSS_STATUS_UNAVAIL;
- 	      no_data = 0;
- 	      nss_gethostbyname4_r fct4
- 		= __nss_lookup_function (nip, "gethostbyname4_r");