caddy-frontend: Do not emit garbage during validation

Promises will fail with stderr filled, and it can be such if sha256sum emits
error messages, so just discard them.

software/caddy-frontend/buildout.hash.cfg

@@ -94,11 +94,11 @@ md5sum = b9f73f6323f9fceea054c46c854d2862
 
 [template-graceful-script]
 filename = templates/graceful-script.sh.in
-md5sum = 31dd34de4c40a1d814bcbef482c757cc
+md5sum = 2c5f15b3906dc64a76d7e88d6dee8dfe
 
 [template-validate-script]
 filename = templates/validate-script.sh.in
-md5sum = 4c80ba3727c397f8d5b12cf1888cf959
+md5sum = a23831f38b7d3aca6639e12f115f4a79
 
 [caddyprofiledeps-setup]
 filename = setup.py

software/caddy-frontend/templates/graceful-script.sh.in

@@ -4,7 +4,7 @@ SIGNATURE_FILE={{ signature_file }}
 NSIGNATURE_FILE={{ signature_file }}.tmp
 
 touch $SIGNATURE_FILE
-{{ sha256sum }} {{ path_list }} | sort -k 66 > $NSIGNATURE_FILE
+{{ sha256sum }} {{ path_list }} | sort -k 66 > $NSIGNATURE_FILE 2> /dev/null
 
 # If no diff, no restart for now
 if diff "$SIGNATURE_FILE" "$NSIGNATURE_FILE" > /dev/null ; then

software/caddy-frontend/templates/validate-script.sh.in

@@ -7,7 +7,7 @@ NSIGNATURE_FILE={{ signature_file }}.tmp
 SIGNATURE_STATUS={{ signature_file }}.status
 
 touch $SIGNATURE_FILE
-{{ sha256sum }} {{ path_list }} | sort -k 66 > $NSIGNATURE_FILE
+{{ sha256sum }} {{ path_list }} | sort -k 66 > $NSIGNATURE_FILE 2> /dev/null
 
 if diff "$SIGNATURE_FILE" "$NSIGNATURE_FILE" > /dev/null; then
   rm -f "$NSIGNATURE_FILE"