ENH: feedstock script should fail on error

Update sed command to not raise inconsequential error code

Author: effigies

tools/feedstock.sh

@@ -25,7 +25,7 @@
 #
 # 2018 Chris Markiewicz
 
-set -x
+set -ex
 
 REPO=${1:-$CIRCLE_PROJECT_REPONAME}
 FEEDSTOCK=${2:-$REPO-feedstock}
@@ -77,7 +77,7 @@ fi
 
 # Set version, hash, and reset build number
 # Use ~ for separator in URL, to avoid slash issues
-sed -i '' \
+sed -i \
     -e 's/^\({% set version = "\).*\(" %}\)$/'"\1$VERSION\2/" \
     -e 's/^\({% set sha256 = "\).*\(" %}\)$/'"\1$SHA256\2/" \
     -e 's~^\( *url:\) .*$~\1 '"$URL_FMT~" \