Additional Deb build changes partly related to WL#13985

 - Use "Architecture: any" in "control" to get architecture
   "amd64" or "i386" in package names
 - Test if BYTE_CODE_ONLY is empty or not as condition,
   not a specific value in "rules"
 - Use a separate variable "BYTE_CODE_ONLY_OPT" in "rules"
   that conditionally is set to "--byte-code-only" if
   BYTE_CODE_ONLY is set in the environment

Update Protobuf version to >=3.0.0 in requirements

Update CPYINT revision

Fix segmentation fault due to import order

Update of the license files

- Fixed the formatting in license text for C/Python 8.0.17 release

- CPYINT branch:53ac01

BUG29521636: Add missing mysqlx_prepare_pb2.py file in MSI product.wxs

Prepare release 8.0.15

BUG29034868: Fix wrong WL number in CHANGES.txt

BUG28673129: Client.close() method raises socket error on Py2.7

A second call to the close method of Client can raise a
sockect error. This seems to be a different behavios in the
sockect library on Python 2.7, This Patch adds a try catch
to avoid raising the error.

This patch also fixes some failing unittests on Pb2 machines.