CLEANUP: Stop checking the pointer before calling `pool_free()`

Changes performed with this Coccinelle patch:

    @@
    expression e;
    expression p;
    @@

    - if (e != NULL) {
    	pool_free(p, e);
    - }

    @@
    expression e;
    expression p;
    @@

    - if (e) {
    	pool_free(p, e);
    - }

    @@
    expression e;
    expression p;
    @@

    - if (e)
    	pool_free(p, e);

    @@
    expression e;
    expression p;
    @@

    - if (e != NULL)
    	pool_free(p, e);
4 files changed