Set allocator before goto fail (ros2#546)

Signed-off-by: Borja Outerelo <borjaouterelo@gmail.com>

rcl/src/rcl/init.c

@@ -83,6 +83,9 @@ rcl_init(
   // Zero initialize rmw context first so its validity can by checked in cleanup.
   context->impl->rmw_context = rmw_get_zero_initialized_context();
 
+  // Store the allocator.
+  context->impl->allocator = allocator;
+
   // Copy the options into the context for future reference.
   rcl_ret_t ret = rcl_init_options_copy(options, &(context->impl->init_options));
   if (RCL_RET_OK != ret) {
@@ -151,9 +154,6 @@ rcl_init(
     goto fail;
   }
 
-  // Store the allocator.
-  context->impl->allocator = allocator;
-
   TRACEPOINT(rcl_init, (const void *)context);
 
   return RCL_RET_OK;