Use javaPathHelper for JAVA_HOME default value

Index: bin/ec2-cmd
--- bin/ec2-cmd.orig
+++ bin/ec2-cmd
@@ -15,7 +15,7 @@ __RPM_PREFIX__EC2_HOME=/usr/local/aes/cmdline
 LIBDIR="${EC2_HOME}/lib"
 
 # Check our Java env
-JAVA_HOME=${JAVA_HOME:?JAVA_HOME is not set}
+JAVA_HOME=$(javaPathHelper -h ec2-api-tools)
 
 # If a classpath exists preserve it
 CP="${CLASSPATH}"
