Ensure to always cleanly unmount (e.g., on shutdown) in mount-sd-service
by adding After=udisks2.service, Requires=udisks2.service and an
unconditional ExecStop= (by removing the "-" appended). This change has
been evaluated and tested for a year per mount-sdcard .
Note: Requisite (of dev-%i.device) should behave the same as BindsTo
except on certain failures with layered devices such as USB memory card
reader (UMS + memory card interface). However that should not be a
significant difference otherwise.