revoking GRANT privilege fix

[bodik]

hello,

while trying to implement some basic stuff on mysql/identity management (account lifecycle present,disabled,absent) I came across on a not nice behavior. If user is ever granted a granting option, those cannot be revoked in a fine manner. the "feature" itself is not documented because it's more like side effect.

testcase:

1. mysql_grant( ... options=>['GRANT'])
2. grant is present
3. mysql_grant( ... options=>[])
   3a. mysql_grant( ...)
4. grant is present
5. mysql_grant( ... options=>"")
6. grant is revoked
7. mysql_grant( ... options=>"")
8. grant is revoked again
   ... its revoked everytime

This patch proposes a more proper handling options attribute on grant resource. Initialize option everytime even if it's not present, NONE keyword is not honored in providers cmd_options, so it does not matter and it's backward compatible.

the test and results before and after applying this patch is attached

grandfix1-testlog.txt

[bmjen]

Thanks @bodik