virfile: Resolve Coverity DEADCODE

virfile: Resolve Coverity DEADCODE

Adjust the parentheses in/for the waitpid loops; otherwise, Coverity
points out:

(1) Event assignment:   Assigning: "waitret" = "waitpid(pid, &status, 0) == -1"
(2) Event between:      At condition "waitret == -1", the value of "waitret"
                        must be between 0 and 1.
(3) Event dead_error_condition:     The condition "waitret == -1" cannot
                        be true.
(4) Event dead_error_begin:     Execution cannot reach this statement:
                        "ret = -*__errno_location();".

Signed-off-by: John Ferlan <jferlan@redhat.com>