Switch to `wheezy-slim`, exclude git and curl.

library/fsharp

@@ -6,8 +6,8 @@ Tags: latest, 4, 4.1, 4.1.18
 GitCommit: 2201a2c453ca69249bf6f4c4c121e8bb2a847cf7
 Directory: 4.1.18/mono
 
-Tags: 4.1.18-wheezy
-GitCommit: 0d86b281d7e8fccfe463d098310a5fd521f0276a
+Tags: 4.1.18-wheezy-slim
+GitCommit: 33b5be9aea66ea1d258daf23055fa6d9bcb164ff
 Directory: 4.1.18/mono-wheezy
 
 Tags: 4.1.0.1