Carry the two paths the RHEL family uses as well

The list was four of the six that Go's crypto/x509 and curl both carry.
The missing two are the bundle under /etc/pki/ca-trust, which is where
RHEL 7 and CentOS keep it, and OpenELEC's. Neither is likely and both are
one line.

The rest was checked in containers rather than assumed: the first entry
answers Debian, Ubuntu, Arch, Gentoo, Fedora and Alpine, and openSUSE is
the only common distribution that needs a different one.

dikte/integrate.py

@@ -95,12 +95,18 @@ def restore_library_path():
     return moved
 
 
-# Where the distributions keep the trust store. One list rather than a guess
-# per distribution, in the order curl and Go try them.
+# Where the trust store is, which is not one place but is a short list of them:
+# every distribution takes its layout from one of four packages rather than
+# inventing one, and this is the list Go's crypto/x509 and curl both carry. The
+# first line alone answers Debian, Ubuntu, Arch, Gentoo, Fedora and Alpine,
+# which was checked rather than assumed; the rest are the ones that do it their
+# own way.
 CA_FILES = (
-    "/etc/ssl/certs/ca-certificates.crt",   # Debian, Ubuntu, Arch, Gentoo
+    "/etc/ssl/certs/ca-certificates.crt",                 # Debian and everything after it
     "/etc/pki/tls/certs/ca-bundle.crt",                   # Fedora, RHEL
     "/etc/ssl/ca-bundle.pem",                             # openSUSE
+    "/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem",  # RHEL 7 and CentOS
+    "/etc/pki/tls/cacert.pem",                            # OpenELEC
     "/etc/ssl/cert.pem",                                  # Alpine, and macOS
 )
 CA_DIRECTORIES = ("/etc/ssl/certs", "/etc/pki/tls/certs")