Upgrade from OEM 11g to 12c: EM Console Service & EM Jobs Service have status Pending, Database System discovered had no members and status Pending.

We created a new OEM 12c [12.1.0.2.2], using the 2-system upgrade approach from our OEM 11g.
The first agent I installed, in the machine where I installed OMS and repository database had every target discovered with status Up, except the Database System, which had status Pending.
Also, EM Console Service & EM Jobs Service had status Pending.

Strangely, both issues had the same solution.
Although, in our old 11g repository database the parameter job_queue_processes had a value of 1000, some where in the upgrade process, in the new 12c repository database this changed to 0.
Probably, that happened during the database upgrade from 11.2.0.2 to 11.2.0.3 using dbua.

So the solution was:
Run as SYS:

SQL> show parameter job_queue_processes

NAME                TYPE     VALUE
------------------- -------- -----
job_queue_processes integer  0

SQL> ALTER SYSTEM SET job_queue_processes=1000 SCOPE=BOTH;
System altered.

SQL> show parameter  job_queue_processes

NAME                TYPE     VALUE
------------------- -------- -----
job_queue_processes integer  1000

Run as SYSMAN:

SQL> exec  emd_maintenance.remove_em_dbms_jobs;
PL/SQL procedure successfully completed.

SQL> exec emd_maintenance.submit_em_dbms_jobs;
PL/SQL procedure successfully completed.