[bin][makeinstall] fix filename arg parse

bin/make_installscript.py

@@ -109,7 +109,9 @@ def runMakeInstallScript():
     modName = getModuleInfo(modPath, "Module")
     printProgressInfo([f"Creating install script for module '{modName}' in folder '{modPath}'"])
 
-    scriptName = cmdArgs.get("filename", getDefaultScriptName(modName, cmdArgs["language"]))
+    scriptName = cmdArgs.get("filename")
+    if not scriptName:
+        scriptName = getDefaultScriptName(modName, cmdArgs["language"])
 
     makeInstallScript(
         modPath=modPath,