FIX: code typo

```
workerm@notebook:~$ subuser install-from-registry
Traceback (most recent call last):
  File "/home/workerm/subuser/logic/subuserCommands/install-from-registry", line 55, in <module>
    installFromRegistry(useCache) 
  File "/home/workerm/subuser/logic/subuserCommands/install-from-registry", line 30, in installFromRegistry
    resetRegistry()
  File "/home/workerm/subuser/logic/subuserCommands/install-from-registry", line 24, in resetRegistry
    if not subuser.dockerImages.isProgramsImageInstalled(program):
NameError: global name 'subuser' is not defined
workerm@notebook:~$ 

```