put bandit tests into maintainer mode

Makefile.am

 # Process this file with automake to produce Makefile.in
-SUBDIRS = libcdi src/lib/ncl src contrib test/data test test/bandit_tests
+SUBDIRS = libcdi src/lib/ncl src contrib test/data test
+if MAINTAINER_MODE
+SUBDIRS += test/bandit_tests
+endif
 #
 EXTRA_DIST=config/default OPERATORS doc/cdo.pdf doc/cdo_cmor.pdf doc/cdo_eca.pdf doc/cdo_magics.pdf doc/cdo_refcard.pdf cdo.spec README
 #