[LyX/master] Don't guess whether autosave succeeded

[Georg Baum]

commit 50467f3f554129b6ff532f4433da27e9b76aff55
Author: Georg Baum <b...@lyx.org>
Date:   Fri Jul 4 21:06:49 2014 +0200

    Don't guess whether autosave succeeded
    
    writeFile() tells whether it could save the file, so use the return value
    instead of guessing.

diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index 10e7a27..4331309 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -3738,9 +3738,9 @@ int AutoSaveBuffer::generateChild()
        tempfile.setAutoRemove(false);
        FileName const tmp_ret = tempfile.name();
        if (!tmp_ret.empty()) {
-               buffer_.writeFile(tmp_ret);
-               // assume successful write of tmp_ret
-               if (!tmp_ret.moveTo(fname_))
+               if (!buffer_.writeFile(tmp_ret))
+                       failed = true;
+               else if (!tmp_ret.moveTo(fname_))
                        failed = true;
        } else
                failed = true;