[gfortran] Remove gfc_current_locus() and gfc_set_locus() (Followup to scanner rewrite)

[Tobias Schlüter]

Tobias Schlüter wrote:
> This meant performing three replacements:
> 1. x = *gfc_current_locus () -> x = gfc_current_locus
> 2. x = gfc_current_locus () -> x = &gfc_current_locus
> 3. gfc_set_locus (x) -> gfc_current_locus = *x
> 
> All this was done with sed. Compiled and tested with no regressions on
> i686-pc-linux.
> 
I forgot to mention that a patch which only removed gfc_current_locus() 
passed Steve's testsuite with no new failures.

- Tobi