change libproj download location to avoid https

modules/slimFunction/CMakeLists.txt

@@ -57,8 +57,8 @@ if(ENABLE_PROJ)
   endif(WIN32)
   ExternalProject_Add(
     libproj 
-    URL https://github.com/OSGeo/proj.4/archive/4.9.2.tar.gz
-    URL_MD5 a6059d05592948d5f205ba432e359bd7
+    URL http://download.osgeo.org/proj/proj-4.9.2.tar.gz
+    URL_MD5 9843131676e31bbd903d60ae7dc76cf9
     PATCH_COMMAND ${CMAKE_COMMAND} -E remove <SOURCE_DIR>/nad/CMakeLists.txt
     INSTALL_COMMAND ""
     PREFIX libproj