package/libxcrypt: bump version to 4.4.18

package/libxcrypt: bump version to 4.4.18

Drop patch which has been merged into mainline.

LICENSING file identifies individual files in the tree, and some have
moved between 4.4.17 and 4.4.18 (upstream commit 3436c6a94b8d).

Fix two -spaces in hash file as well.

Signed-off-by: Guillaume W. Bres <guillaume.bressaix@gmail.com>
[yann.morin.1998@free.fr:
  - explain license hash change
  - two-spaces in hash file
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>