sandbox/sail: Resolves the redefinition of default argument error with clang.

Relevant error message:
../fstext/prune-special-inl.h:164:26: error: redefinition of default argument
                  size_t max_states = 0) {
                         ^            ~
../fstext/prune-special.h:52:26: note: previous definition is here
                  size_t max_states =  0);
                         ^             ~

git-svn-id: https://svn.code.sf.net/p/kaldi/code/sandbox/sail@3730 5e6a8d80-dfce-4ca6-a32a-6e07a63d50c8

src/fstext/prune-special-inl.h

@@ -161,7 +161,7 @@ template<class Arc>
 void PruneSpecial(const Fst<Arc> &ifst,
                   VectorFst<Arc> *ofst,
                   typename Arc::Weight beam,
-                  size_t max_states = 0) {
+                  size_t max_states) {
   PruneSpecialClass<Arc> c(ifst, ofst, beam, max_states);
 }