Fix invalid use of vector iterator

Once an element of a vector is erased using an iterator, that
iterator should be considered invalid and not used.  The accepted
practice is to update the iterator with the return value of the
erase method and not to increment the iterator.

CQ: SW465848
Change-Id: If6ec7887d8c2b6c6ad44a9608c474b9c118bd117
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/85220
Reviewed-by: Zachary Clark <zach@ibm.com>
Reviewed-by: Michael Baiocchi <mbaiocch@us.ibm.com>
Reviewed-by: Daniel M Crowell <dcrowell@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Nicholas E Bofferding <bofferdn@us.ibm.com>

src/usr/initservice/baseinitsvc/initservice.C

@@ -1060,8 +1060,7 @@ bool InitService::unregisterShutdownEvent(msg_q_t i_msgQ)
     {
 
         for(EventRegistry_t::iterator r = iv_regMsgQ.begin();
-                r != iv_regMsgQ.end();
-                ++r)
+                r != iv_regMsgQ.end();)
         {
             // erase all instances
             if(r->msgQ == i_msgQ)
@@ -1072,7 +1071,11 @@ bool InitService::unregisterShutdownEvent(msg_q_t i_msgQ)
                     r->compID, r->msgQ, r->msgType, r->msgPriority);
 
                 result = true;
-                iv_regMsgQ.erase(r);
+                r = iv_regMsgQ.erase(r);
+            }
+            else
+            {
+                ++r;
             }
         }
     }