Tests whether the specified vault exists, returns true if it does and false if the datavault is locked, does not exist, or is inaccessible for any other reason.
+ (BOOL)vaultExists:(NSString*)name;
Returns true if the vault exists; otherwise returns false.
if ([SUPDataVault vaultExists:@"myVault"])
{
[SUPDataVault deleteVault:@"myVault"];
}