Fix application salt path

[sosthene-nitrokey]

The path was duplicated because it is added in the filestore and in the salt path string

Fix #30

Now the full data looks like this:

[2023-04-26T12:14:34Z ERROR trussed::service] :: PERSISTENT
[2023-04-26T12:14:34Z ERROR trussed::service] p"/backend-auth\0" p(p"/\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/backend-auth/dat\0" p(p"/backend-auth\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/backend-auth/dat/salt\0" p(p"/backend-auth/dat\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test\0" p(p"/\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test/backend-auth\0" p(p"/test\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test/backend-auth/dat\0" p(p"/test/backend-auth\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test/backend-auth/dat/application_salt\0" p(p"/test/backend-auth/dat\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test/backend-auth/dat/pin.00\0" p(p"/test/backend-auth/dat\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test/backend-auth/dat/pin.01\0" p(p"/test/backend-auth/dat\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/trussed\0" p(p"/\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/trussed/dat\0" p(p"/trussed\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/trussed/dat/rng-state.bin\0" p(p"/trussed/dat\0")
[2023-04-26T12:14:34Z ERROR trussed::service] :: EXTERNAL
[2023-04-26T12:14:34Z ERROR trussed::service] :: VOLATILE
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test\0" p(p"/\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test/sec\0" p(p"/test\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test/sec/3ad3b5303bc4ba810cd2c5d10b82a86f\0" p(p"/test/sec\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test/sec/54e25250a97e867e3113400efeb9415e\0" p(p"/test/sec\0")
[2023-04-26T12:14:34Z ERROR trussed::service] p"/test/sec/ff903393fc9b14982e3ecebba17537e4\0" p(p"/test/sec\0")

The salt is in the same directory as the pins.

[sosthene-nitrokey]

I actually think once this is merged we will be able to separate the delete_all_pins and the application key deletion. It failed previously because of the nested directory, but now it shouldn't.

[robin-nitrokey]

Thanks!