[FLOSS] mini plugin fails silently on meta-set

[Bujuhu]

As discussed in #4555

Steps to Reproduce the Problem

$ sudo kdb mount mini.ini user:/tests/mini mini
# RET: 0
$ kdb meta-set user:/tests/mini/key value value
# RET: 0  
$ kdb meta-get user:/tests/mini/key value
Metakey not found
# RET: 2

Expected Result

Should print an error on kdb meta-set user:/tests/mini/key value value and return a non 0 exit code

Actual Result

$ kdb meta-set user:/tests/mini/key value value fails silently and kdb meta-get user:/tests/mini/key value returns Metakey not found

System Information

Operating System:
Arch Linux, Kernel 5.19.13-arch1-1

kdb and plugins version

# kdb --version
KDB_VERSION: 0.9.11
SO_VERSION: 5

Relevant Source Code

While mini explicitly states in its documentation that it does not support metadata, it still doesn't have any warning if a user tries to set a meta key

libelektra/src/plugins/mini/mini.c

Line 280 in cf4b6f3

static inline int writeFile (FILE * file, KeySet * keySet, Key * parentKey)