Remove appfuse mount point directory after unmounting.

Bug: 34691785
Test: Check if there are directories under /mnt/appfuse after
      unmounting.

Change-Id: I00a897dd6d60e20b5ccfdfe2faeabb8a4f489197
diff --git a/CommandListener.cpp b/CommandListener.cpp
index 36249e7..e80bdce 100644
--- a/CommandListener.cpp
+++ b/CommandListener.cpp
@@ -756,6 +756,10 @@
                 PLOG(ERROR) << "Failed to unmount directory.";
                 _exit(-errno);
             }
+            if (rmdir(path.c_str()) != 0) {
+                PLOG(ERROR) << "Failed to remove the mount directory.";
+                _exit(-errno);
+            }
             _exit(android::OK);
         } else {
             LOG(ERROR) << "Unknown appfuse command " << command;