spark-shell intends to set MASTER automatically if we do not provide the option when we start the shell , but there's a problem. 
The condition is "if [[ "x" != "x$SPARK_MASTER_IP" && "y" != "y$SPARK_MASTER_PORT" ]];" we sure will set SPARK_MASTER_IP explicitly, the SPARK_MASTER_PORT option, however, we probably do not set just using spark default port 7077. So if we do not set SPARK_MASTER_PORT, the condition will never be true. We should just use default port if users do not set port explicitly I think.

Signed-off-by: shane-huang <shengsheng.huang@intel.com>

Signed-off-by: shane-huang <shengsheng.huang@intel.com>

This commit makes Spark invocation saner by using an assembly JAR to
find all of Spark's dependencies instead of adding all the JARs in
lib_managed. It also packages the examples into an assembly and uses
that as SPARK_EXAMPLES_JAR. Finally, it replaces the old "run" script
with two better-named scripts: "run-examples" for examples, and
"spark-class" for Spark internal classes (e.g. REPL, master, etc). This
is also designed to minimize the confusion people have in trying to use
"run" to run their own classes; it's not meant to do that, but now at
least if they look at it, they can modify run-examples to do a decent
job for them.

As part of this, Bagel's examples are also now properly moved to the
examples package instead of bagel.

Consistently invoke bash with /usr/bin/env bash in scripts to make code more portable (JIRA Ticket SPARK-817)

each line's object rather than a singleton object so that we can ship
these classes to worker nodes). This is pretty hairy stuff, which would
be nice to avoid in the future by integrating with the interpreter some
other way.