Don't install lua plugin for wireshark 1.12+

Apparently there is a conflict where the lua plugin
conflicts with the built-in dissector for openflow
that is included with 1.12 and up. For now, we will
just not install the plugin. This should fix the
14.10 VM build.

Additionally, I have added a handy function,
version_ge, which compares version numbers in
canonical x.y.z format. Thanks to stackoverflow for
pointing out the incredibly useful sort -V option!

util/install.sh

@@ -74,6 +74,17 @@ fi
 # More distribution info
 DIST_LC=`echo $DIST | tr [A-Z] [a-z]` # as lower case
 
+
+# Determine whether version $1 >= version $2
+# usage: if version_ge 1.20 1.2.3; then echo "true!"; fi
+function version_ge {
+    # sort -V sorts by *version number*
+    latest=`printf "$1\n$2" | sort -V | tail -1`
+    # If $1 is latest version, then $1 >= $2
+    [ "$1" == "$latest" ]
+}
+
+
 # Kernel Deb pkg to be removed:
 KERNEL_IMAGE_OLD=linux-image-2.6.26-33-generic
 
@@ -196,6 +207,7 @@ function of13 {
     cd $BUILD_DIR
 }
 
+
 function wireshark {
     echo "Installing Wireshark"
     if [ "$DIST" = "Fedora" ]; then
@@ -204,6 +216,13 @@ function wireshark {
         $install wireshark tshark
     fi
 
+    echo "Checking Wireshark version"
+    WSVER=`wireshark -v | egrep -o '[0-9\.]+' | head -1`
+    if version_ge $WSVER 1.12; then
+        echo "Wireshark version $WSVER >= 1.12 - returning"
+        return
+    fi
+
     echo "Cloning LoxiGen and building openflow.lua dissector"
     cd $BUILD_DIR
     git clone https://github.com/floodlight/loxigen.git
@@ -233,7 +252,7 @@ function ubuntuOvs {
     OVS_SRC=$BUILD_DIR/openvswitch
     OVS_TARBALL_LOC=http://openvswitch.org/releases
 
-    if [ "$DIST" = "Ubuntu" ] && [ `expr $RELEASE '>=' 12.04` = 1 ]; then
+    if [ "$DIST" = "Ubuntu" ] && version_ge $RELEASE 12.04; then
         rm -rf $OVS_SRC
         mkdir -p $OVS_SRC
         cd $OVS_SRC
@@ -382,7 +401,7 @@ function nox {
     # Apply patches
     git checkout -b tutorial-destiny
     git am $MININET_DIR/mininet/util/nox-patches/*tutorial-port-nox-destiny*.patch
-    if [ "$DIST" = "Ubuntu" ] && [ `expr $RELEASE '>=' 12.04` = 1 ]; then
+    if [ "$DIST" = "Ubuntu" ] && version_ge $RELEASE 12.04; then
         git am $MININET_DIR/mininet/util/nox-patches/*nox-ubuntu12-hacks.patch
     fi