Add a hash-bang as the first line of a shell script

Change-Id: I5b663b036ecb25e952ecd2d998971cc326d4ebdf
diff --git a/core/find-jdk-tools-jar.sh b/core/find-jdk-tools-jar.sh
index 20d7d4d..86f9e06 100755
--- a/core/find-jdk-tools-jar.sh
+++ b/core/find-jdk-tools-jar.sh
@@ -1,3 +1,4 @@
+#!/bin/sh
 if [ "x$ANDROID_JAVA_HOME" != x ] && [ -e "$ANDROID_JAVA_HOME/lib/tools.jar" ] ; then
     echo $ANDROID_JAVA_HOME/lib/tools.jar
 else