Use the term 'directions' for representing the directions

1) The previous 'dir' is incorrect because it should be plural for consistency
based upon the other variable names.

2) 'dir' can be misleading in the context where such a term is also used for
representing a directory, like in our case.

Change-Id: I650cc64c2669286a4d7ef071a2ab3b7b63228977
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>