drmgr memory removal is too verbose

[nathanlynch]

We log two lines per LMB in the successful case. This is pretty unpleasant and causes log rotations on larger partitions where we can be operating on thousands of blocks:

drmgr: -r -c mem -q 5120 -w 30 -d 1 
Validating Memory DLPAR capability...yes.
Found 15499 LMBs currently allocated
node    0    8 CPUs     1018 LMBs
node    1    0 CPUs      989 LMBs
node    2    0 CPUs     1022 LMBs
node    3    0 CPUs     1020 LMBs
node    4    0 CPUs      724 LMBs
node    5    0 CPUs     1020 LMBs
node    6    0 CPUs     1020 LMBs
node    7    0 CPUs     1020 LMBs
node    8    0 CPUs     1020 LMBs
node    9    0 CPUs     1020 LMBs
node   10    0 CPUs     1022 LMBs
node   11    0 CPUs     1020 LMBs
node   12    0 CPUs     1018 LMBs
node   13    0 CPUs     1020 LMBs
node   14    0 CPUs      666 LMBs
Try removing 358 / 989 LMBs from node 1
Initiating kernel DLPAR "memory remove index 0x80002c9b"
Success
Initiating kernel DLPAR "memory remove index 0x80002c9a"
Success
Initiating kernel DLPAR "memory remove index 0x80002c99"
Success
Initiating kernel DLPAR "memory remove index 0x80002c98"
Success
Initiating kernel DLPAR "memory remove index 0x80002c97"
Success
Initiating kernel DLPAR "memory remove index 0x80002c96"
Success
Initiating kernel DLPAR "memory remove index 0x80002c95"
Success
[approximately 10,000 more lines]