Optimize dependencies.

debian/control

@@ -7,7 +7,7 @@ Build-Depends: acl, bc, binutils, bison, build-essential, coreutils, ctorrent,
   efibootmgr, ethtool, fakeroot, flex, fonts-ubuntu, g++, gcc, gcc-multilib,
   gdisk, gettext, git, gnupg2, gpgv2, grep, grub-common, grub-ipxe,
   grub-efi-amd64-bin, grub2-common, grub-pc-bin, gzip, hdparm, kmod,
-  libacl1-dev, libattr1-dev, libdevmapper-dev, libelf-dev, libfuse-dev,
+  libacl1-dev, libattr1-dev, libelf-dev, libfuse-dev,
   libncurses5-dev, libnih-dbus1, libowfat-dev, linux-libc-dev, nasm,
   ncurses-base, netpbm, ntfs-3g, parted, patchutils, perl, plymouth-label,
   qemu-utils, rsync, systemd, sysvinit-utils, tar, udev, udpcast, unzip,