Cleaning up the release tools (firebase#173)

Author: hiranya911

pom.xml

@@ -36,8 +36,8 @@
     </organization>
     <licenses>
         <license>
-            <name>Commercial</name>
-            <url>https://firebase.google.com/terms/</url>
+            <name>Apache License, Version 2.0</name>
+            <url>https://www.apache.org/licenses/LICENSE-2.0.txt</url>
         </license>
     </licenses>
     <developers>

prepare_release.sh

@@ -80,7 +80,7 @@ echo "[INFO] Updating CHANGELOG.md"
 if [ $HOST == "Darwin" ]; then
     sed -i "" -e "1 s/# Unreleased//" "CHANGELOG.md"
 else
-    sed -i -e "1 s/# Unreleased//" "CHANGELOG.md"
+    sed -i -e "/# Unreleased/d" "CHANGELOG.md"
 fi
 
 echo -e "# Unreleased\n\n-\n\n# v${VERSION}" | cat - CHANGELOG.md > TEMP_CHANGELOG.md