fix checksum verification

don't read the checksum using the built-in read command, it inserts a ^M that breaks shasum

tsa/howto/new-machine.mdwn

@@ -49,11 +49,10 @@
 
   * on pauli:
 
-        echo "paste sha256sum output now:" && \
-        read sha256 filename && \
         cd /var/lib/puppet/ssl/ca/requests && \
         ( [ -e $filename ] || (echo "$filename does not exist."; exit 1) ) && \
-        echo -e "$sha256  $filename" | sha256sum -c && \
+        echo "paste sha256sum output followed by control-d: " && \
+        sha256sum -c && \
         puppet ca sign $(basename "$filename" .pem) && \
         echo && \
         echo "--- 8< --- CUT HERE --- 8< ---" && \