Correction of remarks

Author: egarbuz

testgres/plugins/pg_probackup2/pg_probackup2/init_helpers.py

@@ -204,10 +204,10 @@ def __init__(self):
         os.environ["PGAPPNAME"] = "pg_probackup"
         self.delete_logs = delete_logs
 
-        if self.probackup_version.split('.')[0].isdigit:
+        if self.probackup_version.split('.')[0].isdigit():
             self.major_version = int(self.probackup_version.split('.')[0])
         else:
-            print('Pg_probackup version \"{}\" is not correct!'.format(self.probackup_version))
+            print('Pg_probackup version \"{}\" is not correct! Expected that the major pg_probackup version should be a number.'.format(self.probackup_version))
             sys.exit(1)
 
     def test_env(self):