Fix update_backup method (#60)

pyproject.toml

@@ -3,7 +3,7 @@ name = "sophosfirewall-python"
 packages = [
     { include = "sophosfirewall_python" },
 ]
-version = "0.1.34"
+version = "0.1.35"
 description = "Python SDK for Sophos Firewall"
 authors = ["Matt Mullen <matt.mullen@sophos.com>"]
 readme = "README.md"

sophosfirewall_python/templates/updatebackup.j2

@@ -10,23 +10,27 @@
 			<BackupPrefix>{{ BackupPrefix | default("") }}</BackupPrefix>
 			<FTPServer>{{ FTPServer | default("") }}</FTPServer><!-- For FTP -->
 			<Username>{{ Username | default("") }}</Username><!-- For FTP -->
+			{% if Password %}
 			{% if "@hashform" in Password %}
 			<Password hashform="mode1">{{ Password['#text'] }}</Password>
 			{% else %}
 			<Password>{{ Password | default("") }}</Password><!-- For FTP -->
 			{% endif %}
+			{% endif %}
 			<FtpPath>{{ FtpPath | default("") }}</FtpPath><!-- For FTP -->
 			<EmailAddress>{{ EmailAddress | default("") }}</EmailAddress><!--For Mail -->
 			<BackupFrequency>{{ BackupFrequency | default("") }}</BackupFrequency>
 			<Day>{{ Day | default("") }}</Day>
 			<Hour>{{ Hour | default("") }}</Hour>
 			<Minute>{{ Minute | default("") }}</Minute>
 			<Date>{{ Date | default("") }}</Date>
+			{% if EncryptionPassword %}
 			{% if "@hashform" in EncryptionPassword %}
 			<EncryptionPassword hashform="mode1">{{ EncryptionPassword['#text'] }}</EncryptionPassword>
 			{% else %}
 			<EncryptionPassword>{{ EncryptionPassword | default("") }}</EncryptionPassword>
 			{% endif%}
+			{% endif %}
 		</ScheduleBackup>
 	</BackupRestore>
    </Set>