shell/caucase.sh: Tolerate openssl not emitting a "keyid:" prefix.

This whole business of parsing openssl command output is so brittle...

shell/caucase.sh

@@ -358,8 +358,9 @@ storeByAuthorityKeyIdentifier () {
   data="$(cat)"
   keyid="$(printf '%s\n' "$data" \
     | openssl "$1" -text -noout \
-    | grep -A4 '^\s*X509v3 Authority Key Identifier:\s*$' | grep '^\s*keyid:' \
-    | head -n1 | sed -e 's/^\s*keyid://' -e 's/://g')"
+    | grep -A1 '^\s*X509v3 Authority Key Identifier:\s*$' \
+    | grep -v '^\s*X509v3 Authority Key Identifier:\s*$' \
+    | head -n1 | sed -e 's/^\s*\(keyid:\)\?//' -e 's/://g')"
   test $? -ne 0 && return 1
   printf '%s\n' "$data" > "$(printf '%s/%s%s' "$2" "$keyid" "$3")"
 }