Take advantage of the new platform infrastructure to move fs_conv_sol26 out
of the vol directory and remove the annoying Autoconf support for
optionally build it in favor of the platform support. We no longer care
about upgrading inode file servers on DUX, so make fs_conv_DUX4 go away.
When using the install-sh that ships with the source tree, Autoconf
substitutes in a relative path just to be annoying. Define the INSTALL
variables in each individual Makefile so that they find the proper file.
Remove the definitions from Makefile.config so that no one will
accidentally get the wrong ones.
Take advantage of the new platform infrastructure to move fs_conv_sol26 out
of the vol directory and remove the annoying Autoconf support for
optionally build it in favor of the platform support. We no longer care
about upgrading inode file servers on DUX, so make fs_conv_DUX4 go away.
