- fix for https://github.com/OpenChemistry/avogadrolibs/issues/611

--- avogadro/qtplugins/insertfragment/CMakeLists.txt.orig	2021-06-02 21:02:35 UTC
+++ avogadro/qtplugins/insertfragment/CMakeLists.txt
@@ -45,8 +45,8 @@ ExternalProject_Add(crystals
     BUILD_COMMAND ""
     INSTALL_COMMAND ""
 )
+endif()
 install(DIRECTORY "${AvogadroLibs_SOURCE_DIR}/../crystals"
 DESTINATION "${INSTALL_DATA_DIR}/avogadro2"
 PATTERN ".git" EXCLUDE
 )
-endif()
\ No newline at end of file
