[LyX/master] Cmake build: Copy & paste error

[Kornel Benko]

commit 8181c88c2888701769a960dc6e2995ebfd181146
Author: Kornel Benko <kornel at lyx.org>
Date:   Fri Nov 29 14:47:27 2019 +0100

    Cmake build: Copy & paste error
---
 CMakeLists.txt |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 12b81a6..ca9895d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -806,7 +806,7 @@ else()
   if(NOT Python3_Interpreter_FOUND)
     unset(PYTHON_EXECUTABLE CACHE)
     find_package(Python2 2.0 REQUIRED)
-    if(NOT PYTHON_VERSION_STRING VERSION_LESS 2.8)
+    if(NOT Python2_VERSION VERSION_LESS 2.8)
       message(FATAL_ERROR "Python interpreter found, but is not suitable")
     endif()
     set(LYX_PYTHON_EXECUTABLE ${Python2_EXECUTABLE} CACHE FILEPATH "Python to be used by LyX")