[LyX/master] Fix crash

[Juergen Spitzmueller]

commit 38ca174819a5318694211b8703e6e1c7129e1145
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Thu Dec 26 16:36:25 2019 +0100

    Fix crash
---
 src/output_latex.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/output_latex.cpp b/src/output_latex.cpp
index 18c87b1..aca126c 100644
--- a/src/output_latex.cpp
+++ b/src/output_latex.cpp
@@ -1639,7 +1639,7 @@ void latexParagraphs(Buffer const & buf,
 
 		// Do not output empty environments if the whole paragraph has
 		// been deleted with ct and changes are not output.
-		if (pit < runparams.par_end) {
+		if (size_t(pit + 1) < paragraphs.size()) {
 			ParagraphList::const_iterator nextpar = paragraphs.constIterator(pit + 1);
 			Paragraph const & cpar = paragraphs.at(pit);
 			if ((par->layout() != nextpar->layout()