Don't install .gitignore file.

Refs #13337

Code/Mantid/Framework/CMakeLists.txt

@@ -156,7 +156,8 @@ install ( DIRECTORY ../instrument/ DESTINATION ${INBUNDLE}instrument
           DIRECTORY_PERMISSIONS OWNER_READ OWNER_EXECUTE OWNER_WRITE
                                 GROUP_READ GROUP_EXECUTE GROUP_WRITE
                                 WORLD_READ WORLD_EXECUTE WORLD_WRITE
-          PATTERN "*UNIT_TESTING*" EXCLUDE
+          PATTERN "*UNIT_TESTING*" EXCLUDE 
+          PATTERN ".gitignore" EXCLUDE
 )
 
 # Ships .py files but only ship compiled pyd files for supported platforms.