[scripts] make combine_short_segments.sh work with python3 (#3926)

Author: hajime9652

egs/wsj/s5/utils/data/combine_short_segments.sh

@@ -134,7 +134,7 @@ if [ -f $srcdir/utt2uniq ]; then
   # they have to be merged into the same set, and we name that set 'a'
   # (in general, we take the lowest string in lexicographical order).
 
-  cat $dir/uniq_sets | LC_ALL=C python -c '
+  cat $dir/uniq_sets | LC_ALL=C python3 -c '
 import sys;
 from collections import defaultdict
 uniq2orig_uniq = dict()
@@ -158,7 +158,7 @@ while changed:
                  changed = True
 
 for uniq in sorted(uniq2orig_uniq.keys()):
-    print uniq, uniq2orig_uniq[uniq]
+    print(uniq, uniq2orig_uniq[uniq])
 ' > $dir/uniq_to_orig_uniq
   rm $dir/uniq_sets