scripts: do not check for PKCS#8 formatted hostkey.pem on shutdown

Motivation:

The 'dcache' script, which is used to control domain lifecycle,
includes a check to verify the private key of the host credential is in
the correct format.  The RPM and deb packages will run 'dcache stop' to
shutdown all domains before uninstalling dCache.  Currently, if the
host credential has the wrong format, this will silently fail, leaving
the old dCache domains running without an easy way to subsequently shut
them down.

Modification:

Remove the private key format check from the 'stop' operation.

Result:

Uninstalling or upgrading an RPM will stop running domains reliably.

Target: master
Patch: https://rb.dcache.org/r/8740/
Acked-by: Tigran Mkrtchyan
Requires-notes: yes
Requires-book: no
Request: 2.14
Request: 2.13
Request: 2.12
Request: 2.11
Request: 2.10

skel/bin/dcache

@@ -386,7 +386,6 @@ case "$1" in
         . ${lib}/utils.sh
         . ${lib}/services.sh
         checkForNonMigratedDcache
-        checkForPkcs8HostKey
         domains=$(printDomains "$@")
         reverse domains_backward $domains
         for domain in $domains_backward; do