969061 - net-snmpd crash on time out

We need to bump soname because net-snmp-5.7.2-agentx-disconnect-crash.patch
changes ABI (sizeof(netsnmp_agent_session)).
diff -up net-snmp-5.7.2/Makefile.top.tst net-snmp-5.7.2/Makefile.top
--- net-snmp-5.7.2/Makefile.top.tst	2013-07-12 13:54:36.646160556 +0200
+++ net-snmp-5.7.2/Makefile.top	2013-07-12 13:54:40.678146522 +0200
@@ -79,7 +79,7 @@ LINKCC	        = @LINKCC@
 # 5.3 was at 10, 5.4 is at 15, ...  This leaves some room for needed
 # changes for past releases if absolutely necessary.
 #
-LIBCURRENT  = 30
+LIBCURRENT  = 31
 LIBAGE      = 0
 LIBREVISION = 2