ngrep: don't use pcap_restart

libpcap since version 1.8.1 does not export the pcap_restart symbol. Disable
use of this symbol.

Fixes:
http://autobuild.buildroot.net/results/647/647061a6fe8cffe3b083c911a986fa7683cdb8f6/
http://autobuild.buildroot.net/results/d90/d90e4d7c62e5b860f1f0ffb5e4dc545928f91734/
http://autobuild.buildroot.net/results/560/56076caede5c7bfc8a57da3a9dc47d0d22309e79/

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/ngrep/ngrep.mk

@@ -21,7 +21,8 @@ NGREP_CONF_OPTS =  \
 	--with-pcap-includes=$(STAGING_DIR)/usr/include/pcap \
 	--enable-pcre \
 	--with-pcre=$(STAGING_DIR)/usr \
-	--disable-dropprivs
+	--disable-dropprivs \
+	--disable-pcap-restart
 
 NGREP_DEPENDENCIES = libpcap pcre