desktop: Fix Windows signing

[sdsantos]

Got an error signing an exe. create-hsms.sh seems to have been successful. Here is a redacted copy of the logs:

$ sign-windows-exe.sh  OONI-Probe-5.2.2.exe OONI-Probe-5.2.2-signed.exe
....
Engine "pkcs11" set.
Unable to enumerate private keys
Corrupt PE file - current signature not at end of file: OONI-Probe-5.2.2.exe
Corrupt PE file
....

$ delete-hsms.sh
....
Waiting for HSM tokens to die.
All HSM tokens are dead. RIP.
All HSM tokens have been deleted.

We need to retry the singing on AWS and figure out what's wrong with the set up, with @hellais helps. He also holds the physical security keys that would act as a fall back.