Update INSTALL to mention boot.sh

fixes #2

INSTALL

@@ -96,7 +96,10 @@ This section explains how to build and install the OpenFlow
 distribution in the ordinary way using "configure" and "make".
 
 0. Check that you have installed all the prerequisites listed above in
-   the Base Prerequisites section.
+   the Base Prerequisites section. Run `boot.sh` if necessary to create
+   the configure script.
+   
+      % ./boot.sh
 
 1. In the top source directory, configure the package by running the
    configure script.  You can usually invoke configure without any