regparse.c: remove unused variable

* regparse.c (add_ctype_to_cc): suppress a warning by removing
  unused variable.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47601 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

regparse.c

@@ -4160,7 +4160,6 @@ add_ctype_to_cc(CClassNode* cc, int ctype, int not, int ascii_range, ScanEnv* en
   const OnigCodePoint *ranges;
   OnigCodePoint sb_out;
   OnigEncoding enc = env->enc;
-  OnigOptionType option = env->option;
 
   r = ONIGENC_GET_CTYPE_CODE_RANGE(enc, ctype, &sb_out, &ranges);
   if (r == 0) {