component/ca-certificates: don't use implicit `python`

We can not rely on system python here. Explicitly use the python used
by buildout.

component/ca-certificates/buildout.cfg

@@ -16,7 +16,7 @@ url = https://deb.debian.org/debian/pool/main/c/ca-certificates/ca-certificates_
 md5sum = fc1c3ec0067385f0be8ac7f6e670a0f8
 patch-binary = ${patch:location}/bin/patch
 patches =
-  ${:_profile_base_location_}/ca-certificates-any-python.patch#c13b44dfc3157dda13a9a2ff97a9d501
+  ${:_profile_base_location_}/ca-certificates-any-python.patch#41c76d53deda3d0b5442791fd25be243
   ${:_profile_base_location_}/ca-certificates-mkdir-p.patch#02ed8a6d60c39c4b088657888af345ef
   ${:_profile_base_location_}/ca-certificates-no-cryptography.patch#14ad1308623b0d15420906ae3d9b4867
 patch-options = -p0
@@ -24,3 +24,4 @@ configure-command = true
 make-targets = install DESTDIR=@@LOCATION@@ CERTSDIR=certs SBINDIR=sbin
 environment =
   PATH=${xz-utils:location}/bin:%(PATH)s
+  SLAPOS_BUILDOUT_PYTHON=${buildout:executable}

component/ca-certificates/ca-certificates-any-python.patch

@@ -11,13 +11,12 @@
      if line.startswith('CKA_CLASS'):
 --- mozilla/Makefile	2015-12-20 10:49:23.000000000 +0100
 +++ mozilla/Makefile	2016-01-05 20:19:11.006874271 +0100
-@@ -3,7 +3,8 @@
+@@ -3,7 +3,7 @@
  #
  
  all:
 -	python3 certdata2pem.py
-+	for x in 3 '' 2; do type python$$x && break; done >/dev/null \
-+	&& python$$x certdata2pem.py
++	$$SLAPOS_BUILDOUT_PYTHON certdata2pem.py
  
  clean:
  	-rm -f *.crt