Wire compression not enabled for initial sync

Initial sync for identical highly compressible data sets on 4.0, 4.2, 4.4:

Total bytes transferred ("InOctets") is much higher for 4.4 and 4.2 than 4.0, and snappy decompressor metrics show that compression is not being used.

Impact on performance is not certain as I'm not sure whether this test is limited by network bandwidth, but if it is impacting performance, then

• Initial sync time for 4.2 is longer than 4.0 because of this
• Initial sync time for 4.4 is a little less than than 4.0 in spite of this