Fixed the can not kill some process using libprocessgroup

In DoKillProcessGroupOnce function, if process has a child process, pids set
will be clear probability and initialPid will not be killed, when the pid
is equal to initialPid.

Test: manual - start duomi app and remove it use recent apps key
Change-Id: Ifb9f4acacd725d2c367e547d2b5512807bb44fec
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index 1cebb5d..0a42053 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -185,7 +185,7 @@
 
     // Erase all pids that will be killed when we kill the process groups.
     for (auto it = pids.begin(); it != pids.end();) {
-        pid_t pgid = getpgid(pid);
+        pid_t pgid = getpgid(*it);
         if (pgids.count(pgid) == 1) {
             it = pids.erase(it);
         } else {