Further isolate 'cta-admin dr' operations between scheduler backends

At the moment, cta-admin dr ls correctly isolated drives between scheduler backends, but this does not work for the up sub-command (and probably for the others neither):

[root@ctaproductionfrontend14 ~]# cta-admin dr ls
       library                  drive     host desired request status since vid tapepool vo files data MB/s session priority activity            scheduler      instance age reason                                     
  IBMLIB1-LTO8   IBMLIB1-LTO8-F09C4R4 tpsrv445      Up NoMount   Free   459   -        -  -     -    -    -       -        0        - cephProductionRepack ctaproduction   6 -                                          
IBMLIB3-TS1160 IBMLIB3-TS1160-F09C1R2 tpsrv068    Down NoMount   Down   103   -        -  -     -    -    -       -        0        - cephProductionRepack ctaproduction   4 Moving to cephRepack (see operations#1671) 
IBMLIB4-TS1160 IBMLIB4-TS1160-F14C3R4 tpsrv004    Down NoMount   Down   126   -        -  -     -    -    -       -        0        - cephProductionRepack ctaproduction   2 Moving to cephRepack (see operations#1671) 

[root@ctaproductionfrontend14 ~]# cta-admin dr up '.*'
Drive IBMLIB1-LTO8-F09C1R3: set Up.
Drive IBMLIB1-LTO8-F09C1R4: set Up.
Drive IBMLIB1-LTO8-F09C2R3: set Up.
Drive IBMLIB1-LTO8-F09C2R4: set Up.
...
<all cta production instance drives going up>