The osmo-hlr DB schema indicates a hlr_number column and references it as 3GPP
TS 23.008 chapter 2.4.6. However, chapter 2.4.6 refers to the "MSC number",
while the "HLR number" is chapter 2.4.7.
Taking a closer look, 2.4.6 says "The MSC number is [...] stored in the HLR",
while 2.4.7 says "The HLR number may be stored in the VLR". As quite obvious,
the HLR does not store the HLR number. This was a typo from the start.
The osmo-hlr code base so far does not use the hlr_number column at all, so we
get away with renaming the column without any effects on the code base.
However, let's rather make this a new schema version to be safe.
Change-Id: I527e8627b24b79f3e9eec32675c7f5a3a6d25440
a8045daeef