[LyX/master] Fix up 0cf394dd

[Enrico Forestieri]

commit 8ae652eb16d04f6992fc1f28be7b47f7d40017dd
Author: Enrico Forestieri <for...@lyx.org>
Date:   Sun Jun 4 03:28:49 2017 +0200

    Fix up 0cf394dd
---
 src/insets/InsetGraphics.cpp |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/insets/InsetGraphics.cpp b/src/insets/InsetGraphics.cpp
index 16a482f..335c92d 100644
--- a/src/insets/InsetGraphics.cpp
+++ b/src/insets/InsetGraphics.cpp
@@ -947,11 +947,9 @@ string InsetGraphics::prepareHTMLFile(OutputParams const & 
runparams) const
 
 docstring InsetGraphics::xhtml(XHTMLStream & xs, OutputParams const & op) const
 {
-       string const output_file;
-       if (!op.dryrun)
-               prepareHTMLFile(op);
+       string const output_file = op.dryrun ? string() : prepareHTMLFile(op);
 
-       if (output_file.empty()) {
+       if (output_file.empty() && !op.dryrun) {
                LYXERR0("InsetGraphics::xhtml: Unable to prepare file `" 
                        << params().filename << "' for output. File missing?");
                string const attr = "src='" + params().filename.absFileName()