Fixed send_broadcast and fork handling issues.

send_broadcast() was calling run_command_always(char*, bool, int, char*) passing:
    run_command_always(NULL, 20, true, am_args);

I.e., it was passing "true" (!1) as the boolean, and 1 (true) as the
timeout value; the proper call should be:

    run_command_always(NULL, true, 20, am_args);

Also, the code handling failure on child calls was calling _exit(),
which quits dumpstate - it should simply return the function instead.

BUG: 27804637

Change-Id: If8c9b40eddc8b76f92e6d11078dfe446a39ad4d4