Set NTFS minimum partition size to 2 MiB (#697848)

The minimum NTFS volume size supported by the ntfs-3g mkntfs command
is 1 MiB.  Since 1 extra sector is required for the backup NTFS boot
sector, an NTFS partition must be at least 1 MiB plus 1 sector.

To demonstrate, create a 1 MiB unformatted partition using MiB
alignment (/dev/sdd1), and then try to format the partition as NTFS.

# mkntfs -Q -v -L "ntfs-test" /dev/sdd1
Device is too small (1023kiB).  Minimum NTFS volume size is 1MiB.

For GParted this means a minimum NTFS partition size of 2 MiB since
the smallest unit in the GUI is MiB.

Bug #697848 - Failure to Create 1 MiB NTFS Partition

src/ntfs.cc

@@ -105,6 +105,11 @@ FS ntfs::get_filesystem_support()
 
 	fs .online_read = FS::GPARTED ;
 
+	//Minimum NTFS partition size = (Minimum NTFS volume size) + (backup NTFS boot sector)
+	//                            = (1 MiB) + (1 sector)
+	// For GParted this means 2 MiB because smallest GUI unit is MiB.
+	fs. MIN = 2 * MEBIBYTE;
+
 	return fs ;
 }