Change the INSTALL documentation for unified builds

Because of the unified scheme, building on different platforms is very
similar.  We currently have Unix and OpenVMS on the unified scheme,
which means that a separate INSTALL.VMS is no longer needed.

Reviewed-by: Matt Caswell <matt@openssl.org>

NOTES.VMS

@@ -0,0 +1,47 @@
+
+ NOTES FOR THE OPENVMS PLATFORM
+ ==============================
+
+ Requirement details
+ -------------------
+
+ In addition to the requirements listed in INSTALL, these are required
+ as well:
+
+  * At least ODS-5 disk organization for source and build.
+    Installation can be done on any existing disk organization.
+
+
+ About ANSI C compiler
+ ---------------------
+
+ An ANSI C compiled is needed among other things.  This means that VAX C
+ is not and will not be supported.
+
+ We have only tested with DEC C (a.k.a HP VMS C / VSI C), compiling with
+ a different ANSI C compiler may require some work.
+
+
+ Checking the distribution
+ -------------------------
+
+ There have been reports of places where the distribution didn't quite
+ get through, for example if you've copied the tree from a NFS-mounted
+ Unix mount point.
+
+ The easiest way to check if everything got through as it should is to
+ check for one of the following files:
+
+   [.crypto]opensslconf^.h.in
+
+ The best way to get a correct distribution is to download the gzipped
+ tar file from ftp://ftp.openssl.org/source/, use GZIP -d to uncompress
+ it and VMSTAR to unpack the resulting tar file.
+
+ Gzip and VMSTAR are available here:
+
+   http://antinode.info/dec/index.html#Software
+
+ Should you need it, you can find UnZip for VMS here:
+
+   http://www.info-zip.org/UnZip.html