Refactor the unmount part of the initrd context shutdown

packages/base/all/vendor-config-onl/src/python/onl/install/InstallUtils.py

@@ -834,7 +834,7 @@ class InitrdContext(SubprocessMixin):
 
         return self
 
-    def shutdown(self):
+    def unmount(self):
 
         p = ProcMountsParser()
         if self.dir is not None:
@@ -852,6 +852,10 @@ class InitrdContext(SubprocessMixin):
                 cmd = ('umount', p,)
                 self.check_call(cmd, vmode=self.V1)
 
+    def shutdown(self):
+
+        self.unmount()
+
         if self.initrd and self.dir:
             self.log.debug("cleaning up chroot in %s", self.dir)
             self.rmtree(self.dir)