Add /sbin/grub check.

pym/cl_install.py

@@ -1472,6 +1472,8 @@ class cl_install(color_print, SignalInterrupt):
 
         Perform grub installation to disk, which has root partition
         """
+        if not path.exists('/sbin/grub'):
+            raise DistributiveError(_("Cann't install bootloader"))
         grubProcess = process("/sbin/grub",
                "--device-map=%s/boot/grub/device.map"%target.getDirectory(),
                "--batch",stderr=STDOUT)