Allow specifying human readable value for option `memory_limit` again (#4049)

lib/ansible/modules/cloud/docker/_docker.py

@@ -566,6 +566,8 @@ def _human_to_bytes(number):
 
     if isinstance(number, int):
         return number
+    if number.isdigit():
+        return int(number)
     if number[-1] == suffixes[0] and number[-2].isdigit():
         return number[:-1]
 
@@ -1870,7 +1872,7 @@ def main():
             volumes_from    = dict(default=None, type='list'),
             links           = dict(default=None, type='list'),
             devices         = dict(default=None, type='list'),
-            memory_limit    = dict(default=0, type='int'),
+            memory_limit    = dict(default=0),
             memory_swap     = dict(default=0, type='int'),
             cpu_shares      = dict(default=0, type='int'),
             docker_url      = dict(),