Fix a bug when trying to disband a faction is perms array is nil

ROADMAP

@@ -290,6 +290,27 @@ mods/pathogen/gravititus/init.lua:36: attempt to index local 'digger' (a nil val
   - [ ] We should be able to change style (#navigation not so large)
     We could replace doc/luadoc.css directly
 
+**** Doesn't run on 5.3.0 client
+     :LOGBOOK:
+     CLOCK: [2020-12-06 dim. 13:52]--[2020-12-06 dim. 14:00] =>  0:08
+     :END:
+ModError: Failed to load and run script from \mods\hopper\init.lua:
+2020-08-16 15:49:47: ERROR[Main]: Unknown node: default:chest
+2020-08-16 15:49:47: ERROR[Main]: stack traceback:
+2020-08-16 15:49:47: ERROR[Main]: 	[C]: in function 'get_content_id'
+2020-08-16 15:49:47: ERROR[Main]: 	...64\bin\..\games\minetest-pvp-master\mods\hopper\init.lua:3: in main chunk
+2020-08-16 15:49:47: ACTION[Main]: Server: Shutting down
+
+see https://dev.minetest.net/Changelog#5.2.0_.E2.86.92_5.3.0
+  =minetest.get_content_id: throw error for unknown nodes (HybridDog)=
+
+- [X] Got a bug in faction \disband 
+  factions.lua:275 bad arg to 'ipairs' (table expected, got nil)
+  A simple =/factions disband= in the chat make the test
+- [ ] Another xpro issue
+  - pasta e/ou arquivo inexiste(s) (em memor.ler)
+    Registro acessado inexiste (xpro/jogador/xo) en memor.consultar)
+- [ ] Factions list not updated till we click on the list widget
 **** DONE [feature_FactionUI] Try to add a factions UI
      :LOGBOOK:
      CLOCK: [2020-03-18 mer. 22:26]--[2020-03-18 mer. 22:41] =>  0:15

TODO

@@ -11,4 +11,4 @@ minetest-solebull - LGPL-2.1 - A PVP/faction game for minetest based on Cobalt.
    
    
 * v0.0.2-9 (27 May 2020 - ???) CLOC ???,???
-
+- (1) Fix a bug when trying to disband a faction is perms array is nil

mods/factions/factions.lua

@@ -272,6 +272,13 @@ function factions.Faction.has_permission(self, player, permission)
         return false
     end
     local perms = self.ranks[p]
+
+    -- Trying to fix a 'bad arg to 'ipairs' (table expected, got nil)' error
+    if perms == nil then
+        minetest.chat_send_player(player, "Can't check your permissions. perms array is nil!")
+       return false
+    end
+    
     for i in ipairs(perms) do
         if perms[i] == permission then
             return true