windows: Always initialize the uv_process_t

The unix implementation of uv_spawn always starts out with a
uv__handle_init, but the windows implementation sometimes bails out early
before calling uv__handle_init. This means that uv_close on a failed
uv_spawn will always succeed on unix but sometimes fail on windows.

This commit lifts the initialization of the uv_process_t above all of the
error checking to ensure that uv_close will always work when uv_spawn
returns an error.

src/win/process.c

@@ -811,6 +811,9 @@ int uv_spawn(uv_loop_t* loop,
   PROCESS_INFORMATION info;
   DWORD process_flags;
 
+  uv_process_init(loop, process);
+  process->exit_cb = options->exit_cb;
+
   if (options->flags & (UV_PROCESS_SETGID | UV_PROCESS_SETUID)) {
     return UV_ENOTSUP;
   }
@@ -827,9 +830,6 @@ int uv_spawn(uv_loop_t* loop,
                               UV_PROCESS_WINDOWS_HIDE |
                               UV_PROCESS_WINDOWS_VERBATIM_ARGUMENTS)));
 
-  uv_process_init(loop, process);
-  process->exit_cb = options->exit_cb;
-
   err = uv_utf8_to_utf16_alloc(options->file, &application);
   if (err)
     goto done;