Use infinity timeout for `gen_server:call/3` in stanchion_server
Use infinity timeout for `gen_server:call/3` in stanchion_server

This was causing timeouts for large bucket deletes, like
this:

```
2012-11-06 19:12:40.260 UTC [error] <0.132.0> webmachine error:
path="/buckets/REDACTED-BUCKET"
{exit,{timeout,{gen_server,call,[stanchion_server,{delete_bucket,<<"REDACTED-BUCKET">>,<<"REDACTED-KEY">>}]}},[{gen_server,call,2,[{file,"gen_server.erl"},{line,180}]},{stanchion_wm_bucket,delete_resource,2,[{file,"src/stanchion_wm_bucket.erl"},{line,110}]},{webmachine_resource,resource_call,3,[{file,"src/webmachine_resource.erl"},{line,169}]},{webmachine_resource,do,3,[{file,"src/webmachine_resource.erl"},{line,128}]},{webmachine_decision_core,resource_call,1,[{file,"src/webmachine_decision_core.erl"},{line,48}]},{webmachine_decision_core,decision,1,[{file,"src/webmachine_decision_core.erl"},{line,416}]},{webmachine_decision_core,handle_request,2,[{file,"src/webmachine_decision_core.erl"},{line,33}]},{webmachine_mochiweb,loop,1,[{file,"src/webmachine_mochiweb.erl"},{line,87}]}]}
```

basho/stanchion,sdebnath/stanchion