fix ambertools FetchError

packages/ambertools/package.py

@@ -7,8 +7,8 @@ class Ambertools (CMakePackage):
     The libsander and libpbsa libraries use the LGPL license."""
 
     # Set the homepage and download url
-    homepage = "https://ambermd.org/AmberTools.php"
-    url      = "https://ambermd.org/downloads/AmberTools22jlmrcc.tar.bz2"
+    homepage = "http://ambermd.org/AmberTools.php"
+    url      = "http://ambermd.org/downloads/AmberTools22jlmrcc.tar.bz2"
 
     # Set the gitlab accounts of this package maintainers
     maintainers = ['dbeltran', 'elmath']