install: treat target as file by default instead of dir

When using 'install foo bar', bar should be treated as a file copy of
foo, not a directory to be created and into which install foo.

xinstall.c

@@ -247,8 +247,6 @@ main(int argc, char *argv[])
 					make_dirs(argv[argc - 1], 1);
 					*p = '/';
 				}
-			} else {
-				make_dirs(argv[argc - 1], 1);
 			}
 		}
 		enmasse(argc, argv, install);