docs: add FAQ section for README.mysql

Added solution to resolve issues to start mysql on linux.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
db:mysqldb: fix return values

1) added suitable return values.
2) added checking cursor in fetch().

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
Merge branch 'winf-dev' into zhengwang-dev