Fix sonic-installer and 'show version' command crash when database do…

…cker not running issue. (#2183)

Fix sonic-installer and 'show version' command crash when database docker not running issue.

#### Description
    Global variable utilies_common.cli.iface_alias_converter will connect to config DB when initialize itself. If database docker not running, the initialize code will crash. 
    To fix this issue, change the variable to lazy initialize variable with lazy_object_proxy.

#### Motivation and Context

Fix this issue: sonic-net/sonic-buildimage#10434

#### How Has This Been Tested?
    Pass all UT and sonic-buildimage E2E test.

#### Additional Information (Optional)

setup.py

@@ -216,6 +216,7 @@
         'toposort==1.6',
         'www-authenticate==0.9.2',
         'xmltodict==0.12.0',
+        'lazy-object-proxy',
     ],
     setup_requires= [
         'pytest-runner',

show/main.py

@@ -5,6 +5,7 @@
 import re
 
 import click
+import lazy_object_proxy
 import utilities_common.cli as clicommon
 from sonic_py_common import multi_asic
 import utilities_common.multi_asic as multi_asic_util
@@ -126,8 +127,8 @@ def run_command(command, display_cmd=False, return_cmd=False):
     if rc != 0:
         sys.exit(rc)
 
-# Global class instance for SONiC interface name to alias conversion
-iface_alias_converter = clicommon.InterfaceAliasConverter()
+# Lazy global class instance for SONiC interface name to alias conversion
+iface_alias_converter = lazy_object_proxy.Proxy(lambda: clicommon.InterfaceAliasConverter())
 
 #
 # Display all storm-control data 

utilities_common/cli.py

@@ -7,6 +7,7 @@
 
 import click
 import json
+import lazy_object_proxy
 import netaddr
 
 from natsort import natsorted
@@ -183,8 +184,8 @@ def alias_to_name(self, interface_alias):
         # interface_alias not in port_dict. Just return interface_alias
         return interface_alias if sub_intf_sep_idx == -1 else interface_alias + VLAN_SUB_INTERFACE_SEPARATOR + vlan_id
 
-# Global class instance for SONiC interface name to alias conversion
-iface_alias_converter = InterfaceAliasConverter()
+# Lazy global class instance for SONiC interface name to alias conversion
+iface_alias_converter = lazy_object_proxy.Proxy(lambda: InterfaceAliasConverter())
 
 def get_interface_naming_mode():
     mode = os.getenv('SONIC_CLI_IFACE_MODE')