Warning clang fix dev

[cvvergara]

Fixes #2216 .

Changes proposed in this pull request:

• Modified src code to eliminate warnings

@pgRouting/admins

[krashish8]

Whenever I look at types like II_t_rt, I wonder what's the meaning of it. I need to go back and check for similar types in the include/c_types directory (i_rt.h, ii_t_rt.h, iid_t_rt.h) to understand it's meaning.

Would it be better if full names were used in the types, or can we document or generalize this for better understanding?

I_rt contains a single integer.
IID_t_rt contains two integers and a double type.
But II_t_rt contains two "union" types, each of which contains 3 integers. It looks it should have been "two integers" instead, if we try to generalize it using the short form names.