[LyX/master] ePub: fix argument handling in Python script.

[Thibaut Cuvelier]

commit 7472be428ea0fe23daad655bf815cd851e7f3119
Author: Thibaut Cuvelier <tcuvelier at lyx.org>
Date:   Sun Feb 7 01:55:29 2021 +0100

    ePub: fix argument handling in Python script.
---
 lib/scripts/docbook2epub.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/lib/scripts/docbook2epub.py b/lib/scripts/docbook2epub.py
index a75c458..d01f3e2 100644
--- a/lib/scripts/docbook2epub.py
+++ b/lib/scripts/docbook2epub.py
@@ -21,7 +21,7 @@ import zipfile
 import glob
 
 if __name__ == '__main__':
-    if len(sys.argv) != 3:
+    if len(sys.argv) != 4:
         sys.exit(1)
     own_path, java_path, input, output = sys.argv
     script_folder = os.path.dirname(own_path) + '/../'