Move all drivers to /usr/lib/drivers

This makes them harder to accidentally run them from the shell, which
would not work. In the future this may also allow embedding the driver
config in the driver executable itself without having to look at all
non-driver executables too.

pcid/src/driver_handler.rs

@@ -28,6 +28,11 @@ impl DriverHandler {
 
         let mut args = args.iter();
         if let Some(program) = args.next() {
+            let program = if program.starts_with('/') {
+                program.to_owned()
+            } else {
+                "/usr/lib/drivers/".to_owned() + program
+            };
             let mut command = Command::new(program);
             for arg in args {
                 if arg.starts_with("$") {