If opening any of the log files fail, MaxScale doesn't start before the cause has been removed. Added informative error message which is to be printed to standard error output.
Merge branch 'develop' of https://github.com/mariadb-corporation/MaxScale into develop
Fixes to Coverity cases 72678 (retry), 72693
Added mysqld_error.h in dbusers

Added mysqld_error.h in dbusers
Added 'make documentation' target to CMake that generates documentation with Doxygen.
Fixes to Coverity tasks : 73267, 72686, 72672
Cleaned up warnings, and added checks to malloc return values and error log writes in case of failures.
Merge branch 'develop' of https://github.com/mariadb-corporation/MaxScale into develop
Fixed Coverity tasks : 72722, 72706
Merge branch 'develop' into MAX-316