rebuild pulsar-qld-blast: merge nvme volumes

[cat-bro]

I don't think we have control over the volumes - we may have to ask someone at Nectar in QLD.

pulsar-qld-blast seems to have more than one volume, of which is it using only one. The one that is named 'cvmfs_cache' is not used for the cvmfs cache, which is better off on the bigger volume anyway. One big volume would be better than two smaller ones.

cat@pulsar-qld-blast:~$ df -h
Filesystem                               Size  Used Avail Use% Mounted on
udev                                     106G     0  106G   0% /dev
tmpfs                                     22G  2.0M   22G   1% /run
/dev/vda1                                 50G  9.4G   38G  20% /
tmpfs                                    106G     0  106G   0% /dev/shm
tmpfs                                    5.0M     0  5.0M   0% /run/lock
tmpfs                                    106G     0  106G   0% /sys/fs/cgroup
/dev/mapper/VG_nvme_disk-LV_blast        2.5T  376G  2.0T  16% /mnt
/dev/mapper/VG_nvme_disk-LV_cvmfs_cache  440G   28K  417G   1% /mnt/var/cvmfs
cvmfs2                                   1.2T  357G  845G  30% /cvmfs/cvmfs-config.cern.ch
cvmfs2                                   1.2T  357G  845G  30% /cvmfs/data.galaxyproject.org
tmpfs                                     22G     0   22G   0% /run/user/7012
cat@pulsar-qld-blast:~$ lsblk
NAME                          MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
vda                           252:0    0    50G  0 disk
└─vda1                        252:1    0    50G  0 part /
nvme1n1                       259:0    0   1.5T  0 disk
├─VG_nvme_disk-LV_cvmfs_cache 253:0    0 447.1G  0 lvm  /mnt/var/cvmfs
└─VG_nvme_disk-LV_blast       253:1    0   2.5T  0 lvm  /mnt
nvme0n1                       259:1    0   1.5T  0 disk
└─VG_nvme_disk-LV_blast       253:1    0   2.5T  0 lvm  /mnt