iputils: really remove patch

It seems the appropiate git rm was missing from 8461038f. Fixes:
http://autobuild.buildroot.net/results/1b1/1b1f63e8c7ba10d4055fb422af6a15c044efc9a6/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/iputils/0001-ping-link-against-libm.patch

@@ -1,29 +0,0 @@
-From 8d189e73e660a637ae3f5a604448103ea42e397d Mon Sep 17 00:00:00 2001
-From: Martin Bark <martin@barkynet.com>
-Date: Fri, 12 Feb 2016 16:52:19 +0000
-Subject: [PATCH] ping: link against libm
-
-This commit links ping against libm because ping.c calls the math library
-function finite().
-
-Signed-off-by: Martin Bark <martin@barkynet.com>
----
- Makefile | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/Makefile b/Makefile
-index 8b37c42..fb80f6f 100644
---- a/Makefile
-+++ b/Makefile
-@@ -156,7 +156,7 @@ LIB_clockdiff = $(LIB_CAP)
- DEF_ping_common = $(DEF_CAP) $(DEF_IDN)
- DEF_ping6_common = $(DEF_CAP) $(DEF_IDN)
- DEF_ping  = $(DEF_CAP) $(DEF_IDN) $(DEF_WITHOUT_IFADDRS)
--LIB_ping  = $(LIB_CAP) $(LIB_IDN) $(LIB_RESOLV)
-+LIB_ping  = $(LIB_CAP) $(LIB_IDN) $(LIB_RESOLV) -lm
- 
- ping: ping_common.o ping6_common.o
- ping.o ping_common.o ping6_common.o: ping.h in6_flowlabel.h
--- 
-2.7.0
-