Fix unused warnings

http://ci.rvm.jp/results/trunk_gcc7@silicon-docker/2539622
```
/tmp/ruby/v2/src/trunk_gcc7/class.c: In function 'rb_scan_args_parse':
/tmp/ruby/v2/src/trunk_gcc7/class.c:1971:12: warning: unused variable 'tmp_buffer' [-Wunused-variable]
     VALUE *tmp_buffer = arg->tmp_buffer;
            ^~~~~~~~~~
```
```
In file included from /tmp/ruby/v2/src/trunk_gcc7/vm_insnhelper.c:1895:0,
                 from /tmp/ruby/v2/src/trunk_gcc7/vm.c:349:
/tmp/ruby/v2/src/trunk_gcc7/vm_args.c:212:1: warning: 'args_stored_kw_argv_to_hash' defined but not used [-Wunused-function]
 args_stored_kw_argv_to_hash(struct args_info *args)
 ^~~~~~~~~~~~~~~~~~~~~~~~~~~
```

0 files changed, 0 insertions, 0 deletions