Revert "Remove ssl context variables from Polaris context if compiled…

… out."

We cannot remove these. Internally, polaris.c accesses them if POLARIS_USE_TLS
is enabled _when polaris.c is compiled_. But if the user application does not
set POLARIS_USE_TLS when they compile and instantiate PolarisContext_s, the
context they create will be smaller than polaris.c is expecting and will cause a
buffer overflow.

c/src/point_one/polaris/polaris.h

@@ -118,12 +118,10 @@ struct PolarisContext_s {
  PolarisCallback_t rtcm_callback;
  void* rtcm_callback_info;
 
-#ifdef POLARIS_USE_TLS
  // Note: We're using void* to avoid needing the inclusion of SSL libs in the
  // header file.
  void* ssl_ctx;
  void* ssl;
-#endif // POLARIS_USE_TLS
 };
 
 #ifdef __cplusplus