Making IPython PySpark compatible across versions <1.0.0. Also cleaned up '-i'...

Making IPython PySpark compatible across versions <1.0.0. Also cleaned up '-i' option and made IPYTHON_OPTS work

pyspark

@@ -59,7 +59,12 @@ if [ -n "$IPYTHON_OPTS" ]; then
 fi
 
 if [[ "$IPYTHON" = "1" ]] ; then
-  exec ipython "$IPYTHON_OPTS" "$@"
+  # IPython <1.0.0 doesn't honor PYTHONSTARTUP, while 1.0.0+ does. 
+  # Hence we clear PYTHONSTARTUP and use the -c "%run $IPYTHONSTARTUP" command which works on all versions
+  # We also force interactive mode with "-i"
+  IPYTHONSTARTUP=$PYTHONSTARTUP
+  PYTHONSTARTUP=
+  exec ipython "$IPYTHON_OPTS" -i -c "%run $IPYTHONSTARTUP"
 else
   exec "$PYSPARK_PYTHON" "$@"
 fi