Fix and enable tfproviderlint R002 check: Remove extraneous dereferences in Set() calls

[ryndaniels]

Description

As per tfproviderlint check R002, we want to remove extraneous * dereferences to Set() calls, since Set() automatically handles pointers and the extra * without a nil check can cause a panic.

Failing example:

var stringPtr *string

d.Set("example", *stringPtr)

Should become:

var stringPtr *string

d.Set("example", stringPtr)

Definition of Done

• In GNUmakefile, add -R002 to tfproviderlint command under lint target and have TravisCI testing pass