main/nagios-plugins: fix compilation with wrong mysql-import
This fixes the current build errors on 3.13 builders (like https://build.alpinelinux.org/buildlogs/build-3-13-armv7/main/nagios-plugins/nagios-plugins-2.3.2-r0.log)
This fixes the current build errors on 3.13 builders (like https://build.alpinelinux.org/buildlogs/build-3-13-armv7/main/nagios-plugins/nagios-plugins-2.3.2-r0.log)