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

Changes performed with this Coccinelle patch:

    @@
    expression e;
    @@

    - if (e != NULL) {
    	tasklet_free(e);
    - }

    @@
    expression e;
    @@

    - if (e) {
    	tasklet_free(e);
    - }

    @@
    expression e;
    @@

    - if (e)
    	tasklet_free(e);

    @@
    expression e;
    @@

    - if (e != NULL)
    	tasklet_free(e);

See GitHub Issue #2126
9 files changed