send and show N/A if client or os is empty

src/common/connection.py

@@ -97,7 +97,7 @@ def get_os_info():
 				elif path_to_file.endswith('lfs-release'): # file just has version
 					text = distro_name + ' ' + text
 				return text
-	return ''
+	return 'N/A'
 
 class Connection:
 	"""Connection class"""

src/vcard.py

@@ -101,7 +101,11 @@ class Vcard_window:
 			client += self.os_info[i]['client']
 			os += self.os_info[i]['os']
 			i += 1
-			
+
+		if client == '':
+			client = 'N/A'
+		if os == '':
+			os = 'N/A'
 		self.xml.get_widget('client_name_version_label').set_text(client)
 		self.xml.get_widget('os_label').set_text(os)