ikev2: enforce mandatory KEY_LENGTH on receiving responder child proposal
kernel_alg: override AES_CTR registration key size from PFKEY answer

The PFKEY answer includes the 4 bytes of salt, but we add those
later on and use these values to determine actual key size, not
keymat sizes. This caused aes_ctr128 to be rejected (as kernel
states minimum 'keysize' is 169 (128+32)
alg_info: tidy
pluto: handle AES_CTR_SALT_BYTES
testing: updated ah-pluto-01/description.txt
testing: repurposed ah-pluto-06
testing: ah-pluto-10 changed mismatching algos for additional test
testing: deleted ah-pluto-12 test
updated changes
add AES_CTR_SALT_BYTES to ietf_constants.h
pluto: Add inBytes/outBytes and PLUTO_IN_BYTES= / PLUTO_OUT_BYTES=
testing: added ikev2-27-uniqueid testcase
updated changes
testing: update reference output for ESP_AES_CTR keysize

The kernel gave us the key size plus salt values. We now correct
those to actual key sizes in the pfkey_response registration.
testing: fix "DH 5 for" -> "DH 5" for changed log message
ikev2: send CP reply only when there was a CP request.
Merge branch 'master' of vault.libreswan.org:/srv/src/libreswan
logging: Fix five DBG_log() calls that were not conditional on debug

This showed log messages with "|" symbols even with plutodebug=none
ikev2: use pst st is NULL.
testing: algparse reference output update

- don't try esp=modp1536 - we know it fails and the man page now says dont
  do it.
- add a fflush() so the leak detective output doesn't cut into the output