fix(doctor): update broken command behaviour

frappe/commands/__init__.py

@@ -43,12 +43,14 @@ def pass_context(f):
 
 	return click.pass_context(_func)
 
-def get_site(context):
+def get_site(context, raise_err=True):
 	try:
 		site = context.sites[0]
 		return site
 	except (IndexError, TypeError):
-		raise frappe.SiteNotSpecifiedError
+		if raise_err:
+			raise frappe.SiteNotSpecifiedError
+		return None
 
 def popen(command, *args, **kwargs):
 	output    = kwargs.get('output', True)

frappe/commands/scheduler.py

@@ -126,7 +126,7 @@ def doctor(context, site=None):
 	"Get diagnostic info about background workers"
 	from frappe.utils.doctor import doctor as _doctor
 	if not site:
-		site = get_site(context)
+		site = get_site(context, raise_err=False)
 	return _doctor(site=site)
 
 @click.command('show-pending-jobs')