package/mksh: fix legal-info

package/mksh: fix legal-info

Commit b6b5981f704f (package/mksh: update to R59b) forgot to update the
hash of mksh.1 which is used as the license file. Although the manpage
has changed to accomodate changes in mksh, the licensing blurb has not
changed.

Fixes:
 - http://autobuild.buildroot.org/results/1291917e4b17e087455a6698c4b82e4ff783600d

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[yann.morin.1998@free.fr:
  - expand commit log to state the license has not changed
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>