Cleanup package

Don't uninstall the service manually before proceeding with the upgrade
And run msiexec in %COMSPEC% /C

packages/zabbix_agent.xml

@@ -11,9 +11,6 @@
 
         <check type="uninstall" condition="versiongreaterorequal" path="Zabbix Agent" value="%PKG_VERSION%"/>
 
-        <install cmd='%COMSPEC% /C if exist "%PROGRAMFILES%\Zabbix Agent\zabbix_agentd.exe" "%PROGRAMFILES%\Zabbix Agent\zabbix_agentd.exe" -c "%PROGRAMFILES%\Zabbix Agent\zabbix_agentd.conf" --uninstall'>
-            <exit code="any" />
-        </install>
         <install cmd='msiexec /qn /i "%MSI%" SERVER=%ZBX_SERVER_IP% RMTCMD=0' />
         <install cmd='netsh advfirewall firewall add rule name="Zabbix Agent" dir=in action=allow protocol=TCP localport=10050 enable=yes remoteip=%ZBX_SERVER_IP%' />
         <install cmd='%COMSPEC% /C sc start "Zabbix Agent"'>
@@ -33,7 +30,7 @@
         <remove cmd='%COMSPEC% /C sc stop "Zabbix Agent"'>
             <exit code="any" />
         </remove>
-        <remove cmd='%COMSPEC% /C msiexec /qn /norestart /x "%MSI%"' />
+        <remove cmd='msiexec /qn /norestart /x "%MSI%"' />
         <remove cmd='netsh advfirewall firewall del rule name="Zabbix Agent"' />
 
     </package>