src/db.c: fix: make sure the database is properly closed

Thanks to ASAN, it was discovered that some part of heap
is not released on exit:

  ==19736==ERROR: LeakSanitizer: detected memory leaks

  Indirect leak of 94616 byte(s) in 214 object(s) allocated from:
    #0 0x4e05c6  (/home/wmn/osmocom/osmo-hlr/src/osmo-hlr+0x4e05c6)
    #1 0x7f9b01061dc6  (/usr/lib/x86_64-linux-gnu/libsqlite3.so.0+0x33dc6)

  Indirect leak of 1160 byte(s) in 1 object(s) allocated from:
    #0 0x4e097d  (/home/wmn/osmocom/osmo-hlr/src/osmo-hlr+0x4e097d)
    #1 0x7f9b01061d58  (/usr/lib/x86_64-linux-gnu/libsqlite3.so.0+0x33d58)

  SUMMARY: AddressSanitizer: 95776 byte(s) leaked in 215 allocation(s).

After a long investigation, it was figured out that *sqlite never
closes the database* due to 'unfinalized statements or unfinished
backups'.

The problem was in db_bootstrap(), where several statements were
prepared, but not finalized in loop. This was also the reason of
*.db-shm / *.db-wal files remaining after the program is closed,
and the reason of the following message

  db.c:77 (283) recovered 18 frames from WAL file *.db-wal

Let's fix this and stop ignoring the result of sqlite3_close().

Change-Id: Ibe620d7723b1947d4f60f820bd18435ad0193112
Related: OS#3434
1 file changed