msfcli - fixed impcomplete argument parsing

Before
root@kali ~/metasploit-framework$ msfcli exploit/multi/handler PAYLOAD=windows/meterpreter/reverse_tcp LHOST= E                                                                      ✹msfcli2 
[*] Please wait while we load the module tree...
/opt/metasploit/apps/pro/msf3/lib/msf/core/data_store.rb:91:in `each': The argument could not be parsed correctly. (Rex::ArgumentParseError)
	from /opt/metasploit/apps/pro/msf3/lib/msf/core/data_store.rb:91:in `import_options_from_s'
	from /opt/metasploit/apps/pro/msf3/msfcli:144:in `<main>'
root@kali ~/metasploit-framework$


After
root@kali ~/metasploit-framework$ ./msfcli exploit/multi/handler PAYLOAD=windows/meterpreter/reverse_tcp LHOST= E                                                               1 ↵  ✹msfcli2 
[*] Please wait while we load the module tree...
[!] Error: The argument could not be parsed correctly.

root@kali ~/metasploit-framework$