Minor code refactoring relating set/get back-end DBMS operating system and minor bug fix to properly enforce OS value with --os switch

plugins/dbms/sybase/fingerprint.py

@@ -15,6 +15,7 @@ from lib.core.data import conf
 from lib.core.data import kb
 from lib.core.data import logger
 from lib.core.enums import DBMS
+from lib.core.enums import OS
 from lib.core.session import setDbms
 from lib.core.settings import SYBASE_ALIASES
 from lib.request import inject
@@ -69,7 +70,7 @@ class Fingerprint(GenericFingerprint):
 
             self.getBanner()
 
-            kb.os = "Windows"
+            Backend.setOs(OS.WINDOWS)
 
             return True