MTP: make MTP work even if unplugged and replugged

Set up a loop to keep trying to open / read the MTP device so that
MTP will work even if the device is unplugged during boot or
unplugged and replugged in.

Change-Id: I0d3a3b7c91ce84a8cbed16caa4b15efee35b3641
diff --git a/partitions.hpp b/partitions.hpp
index 8379de9..3cbd8c3 100644
--- a/partitions.hpp
+++ b/partitions.hpp
@@ -219,6 +219,7 @@
 	int Fstab_Processed();                                                    // Indicates if the fstab has been processed or not
 	void Output_Storage_Fstab();                                              // Creates a /cache/recovery/storage.fstab file with a list of all potential storage locations for app use
 	bool Enable_MTP();                                                        // Enables MTP
+	void Add_All_MTP_Storage();                                               // Adds all storage objects for MTP
 	bool Disable_MTP();                                                       // Disables MTP
 	bool Add_MTP_Storage(string Mount_Point);                                 // Adds or removes an MTP Storage partition
 	bool Add_MTP_Storage(unsigned int Storage_ID);                            // Adds or removes an MTP Storage partition