try not to use ThreadInfo::s_threadInfo before it is constructed

Summary: I'm seeing lots of segfaults like:

  0  HPHP::File::TranslatePathKeepRelative(HPHP::String const&) at hphp/runtime/base/file.cpp:62
  1  _M_invoke at hphp/runtime/base/request-injection-data.cpp:144
  2  std::_Function_handler<bool (folly::dynamic const&), void HPHP::IniSetting::Bind<std::basic_fbstring<char, std::char_traits<char>, std::allocator<char>, std::fbstring_core<char> > >(HPHP::Extension const*, HPHP::IniSetting::Mode, std::basic_fbstring<char, std::char_traits<char>, std::allocator<char>, std::fbstring_core<char> > const&, char const*, HPHP::IniSetting::SetAndGet<std::basic_fbstring<char, std::char_traits<char>, std::allocator<char>, std::fbstring_core<char> > >, std::basic_fbstring<char, std::char_traits<char>, std::allocator<char>, std::fbstring_core<char> >*)::{lambda(folly::dynamic const&) 1}>::_M_invoke(std::_Any_data const&, folly::dynamic const&) at third-party2/libgcc/4.8.1/gcc-4.8.1-glibc-2.17-fb/8aac7fc/include/c++/4.8.1/functional:2468
  3  void HPHP::IniSetting::Bind<std::basic_fbstring<char, std::char_traits<char>, std::allocator<char>, std::fbstring_core<char> > >(HPHP::Extension const*, HPHP::IniSetting::Mode, std::basic_fbstring<char, std::char_traits<char>, std::allocator<char>, std::fbstring_core<char> > const&, char const*, HPHP::IniSetting::SetAndGet<std::basic_fbstring<char, std::char_traits<char>, std::allocator<char>, std::fbstring_core<char> > >, std::basic_fbstring<char, std::char_traits<char>, std::allocator<char>, std::fbstring_core<char> >*) at hphp/runtime/base/ini-setting.h:226
  4  HPHP::RequestInjectionData::threadInit() at hphp/runtime/base/ini-setting.h:235
  5  HPHP::RequestInjectionData::RequestInjectionData() at hphp/runtime/base/request-injection-data.h:68
  6  HPHP::ThreadInfo::ThreadInfo() at hphp/runtime/base/thread-info.cpp:52
  7  HPHP::ThreadLocalNoCheck<HPHP::ThreadInfo>::create() at hphp/util/thread-local.h:250
  8  HPHP::ThreadLocalNoCheck<HPHP::ThreadInfo>::getCheck() const at hphp/util/thread-local.h:255
  9  HPHP::init_thread_locals(void*) at hphp/runtime/base/thread-init-fini.cpp:60
  10 HPHP::hphp_process_init() at hphp/runtime/base/program-functions.cpp:1628
  11 HPHP::execute_program_impl(int, char**) at hphp/runtime/base/program-functions.cpp:1431
  12 HPHP::execute_program(int, char**) at hphp/runtime/base/program-functions.cpp:944
  13 main at hphp/hhvm/main.cpp:61

I'm not sure what introduced this recently, but it looks like a legit calling order, and this code I'm changing is probably wrong. Instead of trying to read in the global state, I'll use the local instance as we do in other places while binding other INI settings.

I found this crash going all the way back a month:

-rw------- 1 twsvcscm twsvcscm 4285 Aug  6 15:25 stacktrace.3303.log

Reviewed By: @markw65

Differential Revision: D1546487