Update purple slack

My upstream PR got merged, update package and remove patch.

overlays/purple-slack/call-transformation.patch

@@ -1,23 +0,0 @@
-diff --git a/slack-message.c b/slack-message.c
-index de49fa6..038261d 100644
---- a/slack-message.c
-+++ b/slack-message.c
-@@ -164,6 +164,18 @@ void slack_message_to_html(GString *html, SlackAccount *sa, gchar *s, PurpleMess
- 		}
- 		s = r+1;
- 	}
-+
-+	if (strstr(html->str, "slack.com/call") != NULL) {
-+		gchar *find = g_strconcat(sa->host, "/call", NULL);
-+		gchar *replace = g_strconcat( "app.slack.com/free-willy/", sa->team.id, NULL);
-+		gchar *newHtml = purple_strreplace(html->str, find, replace);
-+
-+		g_string_assign(html, newHtml);
-+
-+		g_free(find);
-+		g_free(replace);
-+		g_free(newHtml);
-+	}
- }
- 
- /*

overlays/purple-slack/default.nix

@@ -5,21 +5,27 @@ self: super: {
     src = super.fetchFromGitHub {
       owner = "dylex";
       repo = "slack-libpurple";
-      rev = "90da1de76425b5d4485c578597be14dbd5b539c8";
-      sha256 = "sha256-WqAQIDN947Wzns8QIZn7MUNmy2s35g0axIC1fjg1YCU=";
+      rev = "f91a5db6f148668afac8384eb349c545308b14fd";
+      sha256 = "sha256-VrkjeE8MYyrjdhmFS4f1OZDN6v69lDKITQQUCj3/1zY=";
     };
 
     # Further ideas to add:
+    # Transform emoticons
     # Add command to react to messages
+    # Support sending of files
     # Prevent duplicates of incoming messages (happens from time to time)
     # Formatting (bold, italic, …) see: https://github.com/dylex/slack-libpurple/pull/122
-    # Transform emoticons
     # Receive reactions
     patches = (old.patches or []) ++ [
+      # 3rd Party
       ./browser-based-auth.patch
-      ./call-transformation.patch
-      ./call-command.patch
+
+      # Own
+      # ./smiley-transformation.patch
       ./open-command.patch
+
+      # Send upstream
+      ./call-command.patch
     ];
   });
 }