d.vect.thematic: Fix Resource Leak issue in plot1.c

[ShubhamDesai]

This pull request fixes issue identified by coverity scan (CID : 1207610, 1207611, 1207612, 1207613, 1207614)
Used Vect_destroy_cats_struct(), Vect_destroy_line_struct(), G_free() to fix this issue.

[nilason]

All the variables primary_color, fill_color, line_color, Points and Cats need to be freed before every exit (return) of the function. The while-statement (L153) is an infinite loop, exiting only in three cases in the if-else-statement of L194-211.

So, instead of adding 5x3 lines of repetitive code, let us add a goto label at the end of the function (adding a ret variable) and free them all there.

[ShubhamDesai]

All the variables primary_color, fill_color, line_color, Points and Cats need to be freed before every exit (return) of the function. The while-statement (L153) is an infinite loop, exiting only in three cases in the if-else-statement of L194-211.

So, instead of adding 5x3 lines of repetitive code, let us add a goto label at the end of the function (adding a ret variable) and free them all there.

done.

[nilason]

Thanks!