`p11-kit list-modules` lists multiple URL entries for the same token with different query attributes

[ueno]

Steps to reproduce:

$ cat softhsm2.conf
directories.tokendir = /tmp/softhsm/
$ mkdir /tmp/softhsm
$ export SOFTHSM2_CONF=$PWD/softhsm2.conf
$ softhsm2-util --init-token --free --label test
$ p11tool --list-tokens
Token 0:
    URL: pkcs11:model=p11-kit-trust;manufacturer=PKCS%2311%20Kit;serial=1;token=System%20Trust
    Label: System Trust
    Type: Trust module
    Flags: uPIN uninitialized
    Manufacturer: PKCS#11 Kit
    Model: p11-kit-trust
    Serial: 1
    Module: p11-kit-trust.so

Token 1:
    URL: pkcs11:model=p11-kit-trust;manufacturer=PKCS%2311%20Kit;serial=1;token=Default%20Trust
    Label: Default Trust
    Type: Trust module
    Flags: uPIN uninitialized
    Manufacturer: PKCS#11 Kit
    Model: p11-kit-trust
    Serial: 1
    Module: p11-kit-trust.so

Token 2:
    URL: pkcs11:model=SoftHSM%20v2;manufacturer=SoftHSM%20project;serial=bf507779ef856d30;token=test
    Label: test
    Type: Generic token
    Flags: RNG, Requires login
    Manufacturer: SoftHSM project
    Model: SoftHSM v2
    Serial: bf507779ef856d30
    Module: /usr/lib64/pkcs11/libsofthsm2.so
$ p11-kit list-modules | grep uri | grep -i softhsm
    uri: pkcs11:library-description=Implementation%20of%20PKCS11;library-manufacturer=SoftHSM?module-name=softhsm2&module-path=%2Fusr%2Flib64%2Fpkcs11%2Flibsofthsm2.so
        uri: pkcs11:model=SoftHSM%20v2;manufacturer=SoftHSM%20project;serial=bf507779ef856d30;token=test?module-name=softhsm2&module-path=%2Fusr%2Flib64%2Fpkcs11%2Flibsofthsm2.so
        uri: pkcs11:model=SoftHSM%20v2;manufacturer=SoftHSM%20project;serial=;token=?module-name=softhsm2&module-path=%2Fusr%2Flib64%2Fpkcs11%2Flibsofthsm2.so

As you see, the last coulple of URIs are only different in the presence of module-path, which is a query attribute (not a path attribute) and should be aggregated.

[ueno]

This might be actually an issue in p11tool (GnuTLS), as the second token (with empty label) exists but not initialized.