use ${SWIG} instead of explicit swig in configure
use ${SWIG} instead of explicit swig in configure

thanks Paul Bünau for the report

Saurabh7/shogun,lambday/shogun,shogun-toolbox/shogun,geektoni/shogun,besser82/shogun,Saurabh7/shogun,besser82/shogun,besser82/shogun,shogun-toolbox/shogun,besser82/shogun,besser82/shogun,shogun-toolbox/shogun,karlnapf/shogun,sorig/shogun,sorig/shogun,Saurabh7/shogun,shogun-toolbox/shogun,lisitsyn/shogun,besser82/shogun,geektoni/shogun,sorig/shogun,Saurabh7/shogun,sorig/shogun,sorig/shogun,Saurabh7/shogun,Saurabh7/shogun,Saurabh7/shogun,lisitsyn/shogun,lambday/shogun,geektoni/shogun,sorig/shogun,lambday/shogun,lisitsyn/shogun,geektoni/shogun,karlnapf/shogun,lisitsyn/shogun,karlnapf/shogun,geektoni/shogun,karlnapf/shogun,Saurabh7/shogun,lambday/shogun,lambday/shogun,lisitsyn/shogun,shogun-toolbox/shogun,Saurabh7/shogun,karlnapf/shogun,lisitsyn/shogun,lambday/shogun,karlnapf/shogun,shogun-toolbox/shogun,geektoni/shogun