Task #8691: ObservationStartListener: fix more wrong usages of parser.error()

LCS/MessageDaemons/ObservationStartListener/src/ObservationStartListener.py

@@ -251,7 +251,7 @@ def checkArgs(parser, options, leftOverArgs):
 
     options.execPath = os.path.abspath(options.execPath)  # for -d or systemd
     if not os.path.isfile(options.execPath) or not os.access(options.execPath, os.X_OK):
-        parser.error('--exec (-x): No such executable file at %s', options.execPath)
+        parser.error('--exec (-x): No such executable file at ' + options.execPath)
 
     options.msgSaveDir = os.path.abspath(options.msgSaveDir)  # for -d or systemd
     if options.msgSaveDir and options.msgSaveDir[-1] != os.path.sep:
@@ -260,11 +260,11 @@ def checkArgs(parser, options, leftOverArgs):
         os.makedirs(options.msgSaveDir)  # exist_ok=True only since Python 3.2
     except OSError as exc:
         if exc.errno != os.errno.EEXIST or not os.path.isdir(options.msgSaveDir):
-            parser.error('--msg-save-dir (-m): Failed to create %s: %s',
-                         exc.filename, exc.strerror)
+            parser.error('--msg-save-dir (-m): Failed to create %s: %s' %
+                         (exc.filename, exc.strerror))
 
     if leftOverArgs:
-        parser.error('unused command line arguments: %s' % leftOverArgs)
+        parser.error('unused command line arguments: ' + leftOverArgs)
 
 def main(args):
     """