Init: Fix superfluous path separate at end

When no path is provided, then the resulting path has no path separator
at the end.
When a path is provided, the old behaviour was that the resulting path
had a separator at the end.
That is not only inconsistent it also broke the autocommands to open
files in the dist folder as readonly.

plugin/vim-bob.vim

@@ -48,7 +48,7 @@ function! s:EscapeForMakeprg(text)
 endfunction
 
 function! s:Init(path)
-	let l:bob_base_path = empty(a:path) ? getcwd() : fnamemodify(a:path, ':p')
+	let l:bob_base_path = empty(a:path) ? getcwd() : fnamemodify(a:path, ':p:h')
 	" not using `--directory` but `cd` instead, because when running inside of
 	" a container via `g:bob_prefix` we would pass the path on the host to Bob
 	" running in the container, where the path is very likely different