Instead of 20, use the actual buffer sizes of struct sw_load, which are 255.
Previous code would truncate a longer string at 20 without(!) NUL termination.
In the _len members, store the actual length copied. In previous code, if the
source string were longer than 20, we would store only 20 (without NUL term)
but still reflect the longer length of the source string.
Fix both of these issues for sw_load.file_id / file_id_len and
sw_load.file_version / file_version_len.
Change-Id: I2e34a1348a290d3f58dd830d08da65b94b3270db
Neels Hofmeyr
1fe2647c5d