Simplify return & fshut() logic

Get rid of the !!()-constructs and use ret where available (or introduce it).

In some cases, there would be an "abort" on the first fshut-error, but we want
to close all files and report all warnings and then quit, not just the warning
for the first file.

unexpand.c

@@ -168,7 +168,7 @@ main(int argc, char *argv[])
 		}
 	}
 
-	efshut(stdin, "<stdin>");
-	efshut(stdout, "<stdout>");
+	ret |= fshut(stdin, "<stdin>") | fshut(stdout, "<stdout>");
+
 	return ret;
 }