Returns the index of a vgroup attribute given its name.
Return value
Returns the index of an attribute if successful and FAIL (or -1) otherwise.
Description
Vfindattr searches the vgroup identified by the parameter vgroup_id for the attribute with the name specified by the parameter attr_name, and returns the index of that attribute.
If more than one attribute has the same name, Vfindattr will return the index of the first one.