657835: IPv6 tests fail instead of being skipped

Detect ipv6 before testing ipv6 transports.

diff -up net-snmp-5.7.2.pre2/testing/fulltests/transports/T320udpv6_simple.rhel net-snmp-5.7.2.pre2/testing/fulltests/transports/T320udpv6_simple

--- net-snmp-5.7.2.pre2/testing/fulltests/transports/T320udpv6_simple.rhel	2012-07-12 04:23:25.000000000 +0200

+++ net-snmp-5.7.2.pre2/testing/fulltests/transports/T320udpv6_simple	2012-07-31 11:10:22.668307328 +0200

@@ -6,6 +6,13 @@ HEADER UDP6 Transport

 SKIPIFNOT NETSNMP_TRANSPORT_UDPIPV6_DOMAIN

+# primitive detection of ipv6

+if test `uname -s` == "Linux" ; then

+    if test ! -e /proc/net/if_inet6; then

+        SKIP

+    fi

+fi

+

 #

 # Begin test

 #

diff -up net-snmp-5.7.2.pre2/testing/fulltests/transports/T330tcpv6_simple.rhel net-snmp-5.7.2.pre2/testing/fulltests/transports/T330tcpv6_simple

--- net-snmp-5.7.2.pre2/testing/fulltests/transports/T330tcpv6_simple.rhel	2012-07-12 04:23:25.000000000 +0200

+++ net-snmp-5.7.2.pre2/testing/fulltests/transports/T330tcpv6_simple	2012-07-31 11:10:07.756378344 +0200

@@ -6,6 +6,13 @@ HEADER TCP6 Transport

 SKIPIFNOT NETSNMP_TRANSPORT_TCPIPV6_DOMAIN

+# primitive detection of ipv6

+if test `uname -s` == "Linux" ; then

+    if test ! -e /proc/net/if_inet6; then

+        SKIP

+    fi

+fi

+

 #

 # Begin test

 #