Add missing 'openssl' command

And turn on error mode in the bash script.

Author: retronym

Diff for: admin/build.sh

@@ -1,5 +1,7 @@
 #!/bin/bash
 
+set -e
+
 # prep environment for publish to sonatype staging if the HEAD commit is tagged
 
 # git on travis does not fetch tags, but we have TRAVIS_TAG
@@ -17,7 +19,7 @@ if [ "$TRAVIS_JDK_VERSION" == "$PUBLISH_JDK" ] && [[ "$TRAVIS_TAG" =~ ^v[0-9]+\.
   K=$encrypted_1ce132863fa7_key
   IV=$encrypted_1ce132863fa7_iv
 
-  aes-256-cbc -K $K -iv $IV -in admin/secring.asc.enc -out admin/secring.asc -d
+  openssl aes-256-cbc -K $K -iv $IV -in admin/secring.asc.enc -out admin/secring.asc -d
 fi
 
 sbt ++$TRAVIS_SCALA_VERSION "$publishVersion" clean update test publishLocal $extraTarget