improve option names and description

Author: aashishc1988

tools/device_management.py

@@ -53,7 +53,7 @@ def __init__(self, *args, **kwargs):
         ).format(self.parser.prog)
         subparserActionLength = len(self.parser._subparsers._actions)
         initParser = self.parser._subparsers._actions[subparserActionLength-1].choices['init']
-        initParser.add_argument('--disable-cert', help='Disable writing the developer certificate to mbed_cloud_dev_credentials.c')
+        initParser.add_argument('--no-developer-cert', help='Do not download the developer certificate')
 
     def _addCreateArgs(self, parser, exclusions=[]):
         if 'payload' not in exclusions:
@@ -134,9 +134,8 @@ def inner(options):
                 "mbed-cli-auto {}".format(api_key.name),
                 description="cetificate auto-generated by Mbed CLI"
             )
-        if getattr(options, 'disable_cert'):
-            LOG.warning("Developer certificate %s not written to "
-                "mbed_cloud_dev_credentials.c", dev_cert_info.name)
+        if getattr(options, 'no_developer_cert'):
+            LOG.info("Skipping download of developer certificate")
         else:
             LOG.info("Writing developer certificate %s into c file "
                  "mbed_cloud_dev_credentials.c", dev_cert_info.name)