COMP: Force extension_description_with_depends.s4ext to use LF EOL in SVN

Extension tests fail because line EOL style difference in extension_description_with_depends.s4ext on different computers with different revision control clients (SVN, git) and operating systems.

To simplify matching of EOL characters, set CMake earlier to generate extension description file with LF style EOL. Now forcing SVN to check out extension_description_with_depends.s4ext using LF style EOL, too.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@25626 3bd1e089-480b-0410-8dfb-8563597acbee