Demand my shell from vim.

Not every system has me logging in as a TCSH user.  Specifically,
qubes guests seem to have trouble with non bourne shells as the
login shell.  For those I use the "start command" feature of
the terminal, but I need to trick VIM into making the shell
be TCSH.

vim/vimrc

@@ -23,3 +23,4 @@ source ~/.vim/vimrc.functions
 source ~/.vim/vimrc.fileprefs
 source ~/.vim/vimrc.statusline
 
+set shell=/bin/tcsh