fix license field

DESCRIPTION

 Package: akima
-Version: 0.5-10
+Version: 0.5-11
 Date: 2013-01-19
 Title: Interpolation of irregularly spaced data
 Author: Fortran code by H. Akima
@@ -8,5 +8,5 @@ Author: Fortran code by H. Akima
  interp2xyz, enhancements and corrections by Martin Maechler <maechler@stat.math.ethz.ch>
 Maintainer: Albrecht Gebhardt <albrecht.gebhardt@uni-klu.ac.at>
 Description: Linear or cubic spline interpolation for irregular gridded data
-License: file LICENSE
+License: ACM | file LICENSE
 Depends: R (>= 2.0.0)