Update OBEX lib setPath Flags handling logic to be compatible with spec.

From IrOBEX, 3.3.6.1, we can see below explanation for Flags bit 1:
1  Don't create directory if it does not exist, return an error instead.
The correct understanding should be: if bit 1 is set to 1, we'll not create
directory if it not exist; if bit 1 is set to 0, we'll create it if it not
exists.