Fix the determining of installation image.

LiveUSB excluded from the list of devices from which you can install the
system if the system installation is on it.

pym/cl_fill_install.py

@@ -736,9 +736,10 @@ class fillVars(object, glob_attr):
                 livedistr = ['/mnt/cdrom']
         else:
             livedistr = []
+        rootDev = self.Get('os_install_root_dev')
         livedistr += \
             map(lambda x:x[0],
-            filter(lambda x:" live" in x[1],
+            filter(lambda x:" live" in x[1] and x[0] != rootDev,
             zip(self.Get('os_disk_dev'),
                 self.Get('os_disk_content'))))
         return ['/var/calculate/remote/linux',