fix multithread_info when THREADS=OFF
fix multithread_info when THREADS=OFF

static members have to be initialized even if deal.II is configured
without multithreading.

lpolster/dealii,lue/dealii,gpitton/dealii,maieneuro/dealii,shakirbsm/dealii,JaeryunYim/dealii,mtezzele/dealii,gpitton/dealii,Arezou-gh/dealii,shakirbsm/dealii,angelrca/dealii,lpolster/dealii,spco/dealii,ESeNonFossiIo/dealii,andreamola/dealii,ESeNonFossiIo/dealii,gpitton/dealii,Arezou-gh/dealii,nicolacavallini/dealii,adamkosik/dealii,EGP-CIG-REU/dealii,nicolacavallini/dealii,JaeryunYim/dealii,pesser/dealii,nicolacavallini/dealii,naliboff/dealii,natashasharma/dealii,kalj/dealii,EGP-CIG-REU/dealii,rrgrove6/dealii,naliboff/dealii,jperryhouts/dealii,ibkim11/dealii,mac-a/dealii,msteigemann/dealii,rrgrove6/dealii,maieneuro/dealii,YongYang86/dealii,maieneuro/dealii,mac-a/dealii,lue/dealii,mtezzele/dealii,danshapero/dealii,JaeryunYim/dealii,ESeNonFossiIo/dealii,EGP-CIG-REU/dealii,mtezzele/dealii,danshapero/dealii,EGP-CIG-REU/dealii,gpitton/dealii,lue/dealii,kalj/dealii,Arezou-gh/dealii,ibkim11/dealii,angelrca/dealii,kalj/dealii,mac-a/dealii,jperryhouts/dealii,msteigemann/dealii,jperryhouts/dealii,johntfoster/dealii,msteigemann/dealii,YongYang86/dealii,pesser/dealii,lue/dealii,andreamola/dealii,gpitton/dealii,shakirbsm/dealii,adamkosik/dealii,ESeNonFossiIo/dealii,rrgrove6/dealii,ibkim11/dealii,angelrca/dealii,rrgrove6/dealii,sairajat/dealii,gpitton/dealii,lpolster/dealii,lpolster/dealii,mac-a/dealii,andreamola/dealii,naliboff/dealii,johntfoster/dealii,natashasharma/dealii,naliboff/dealii,Arezou-gh/dealii,danshapero/dealii,nicolacavallini/dealii,nicolacavallini/dealii,ESeNonFossiIo/dealii,pesser/dealii,YongYang86/dealii,ibkim11/dealii,EGP-CIG-REU/dealii,sriharisundar/dealii,spco/dealii,danshapero/dealii,ibkim11/dealii,spco/dealii,angelrca/dealii,pesser/dealii,rrgrove6/dealii,msteigemann/dealii,ESeNonFossiIo/dealii,pesser/dealii,rrgrove6/dealii,kalj/dealii,spco/dealii,angelrca/dealii,jperryhouts/dealii,nicolacavallini/dealii,nicolacavallini/dealii,spco/dealii,johntfoster/dealii,danshapero/dealii,shakirbsm/dealii,lpolster/dealii,lpolster/dealii,YongYang86/dealii,YongYang86/dealii,natashasharma/dealii,adamkosik/dealii,sairajat/dealii,sriharisundar/dealii,lue/dealii,jperryhouts/dealii,sriharisundar/dealii,sairajat/dealii,andreamola/dealii,sriharisundar/dealii,YongYang86/dealii,mtezzele/dealii,natashasharma/dealii,Arezou-gh/dealii,ibkim11/dealii,msteigemann/dealii,pesser/dealii,lue/dealii,jperryhouts/dealii,mac-a/dealii,mtezzele/dealii,johntfoster/dealii,sriharisundar/dealii,adamkosik/dealii,shakirbsm/dealii,spco/dealii,EGP-CIG-REU/dealii,maieneuro/dealii,sairajat/dealii,JaeryunYim/dealii,johntfoster/dealii,maieneuro/dealii,YongYang86/dealii,danshapero/dealii,ibkim11/dealii,maieneuro/dealii,gpitton/dealii,shakirbsm/dealii,danshapero/dealii,lue/dealii,EGP-CIG-REU/dealii,spco/dealii,adamkosik/dealii,mtezzele/dealii,natashasharma/dealii,kalj/dealii,sairajat/dealii,johntfoster/dealii,naliboff/dealii,mac-a/dealii,adamkosik/dealii,naliboff/dealii,andreamola/dealii,sairajat/dealii,mac-a/dealii,jperryhouts/dealii,andreamola/dealii,maieneuro/dealii,Arezou-gh/dealii,JaeryunYim/dealii,ESeNonFossiIo/dealii,sairajat/dealii,sriharisundar/dealii,mtezzele/dealii,pesser/dealii,rrgrove6/dealii,kalj/dealii,msteigemann/dealii,natashasharma/dealii,adamkosik/dealii,JaeryunYim/dealii,angelrca/dealii,sriharisundar/dealii,Arezou-gh/dealii,lpolster/dealii,JaeryunYim/dealii,johntfoster/dealii,naliboff/dealii,natashasharma/dealii,msteigemann/dealii,kalj/dealii,angelrca/dealii,shakirbsm/dealii,andreamola/dealii