Fix accidental leftover for Linux

In 91aa8bfff8, my understanding of the branch was inverted.

.travis.yml

@@ -422,7 +422,6 @@ before_script:
   - "> .rbconfig.time"
   - sed -f tool/prereq.status template/Makefile.in common.mk > Makefile
   - date; make touch-unicode-files
-  - ls -ltT tool/generic_erb.rb template/unicode_norm_gen.tmpl enc/unicode/data/*/ucd/.unicode-tables.time
   - date; make -s $JOBS $UPDATE_UNICODE up
   - date; make -s $JOBS srcs
   - rm -f config.status Makefile rbconfig.rb .rbconfig.time