vold: Support aborting FUSE connections.

This can be done through binder as well as vdc, using 'vdc volume
abort_fuse'.

Bug: 153411204
Test: adb shell vdc volume abort_fuse
Change-Id: I93e46dc1cd361729cc1162c63520cf73152ea409
diff --git a/VolumeManager.cpp b/VolumeManager.cpp
index f42f3e7..a543573 100644
--- a/VolumeManager.cpp
+++ b/VolumeManager.cpp
@@ -905,6 +905,10 @@
     return 0;
 }
 
+int VolumeManager::abortFuse() {
+    return android::vold::AbortFuseConnections();
+}
+
 int VolumeManager::reset() {
     // Tear down all existing disks/volumes and start from a blank slate so
     // newly connected framework hears all events.
@@ -940,6 +944,7 @@
     mDisks.clear();
     mPendingDisks.clear();
     android::vold::sSleepOnUnmount = true;
+
     return 0;
 }