[SPARK-10511] [BUILD] Reset git repository before packaging source di…

…stro

The calculation of Spark version is downloading
Scala and Zinc in the build directory which is
inflating the size of the source distribution.

Reseting the repo before packaging the source
distribution fix this issue.

Author: Luciano Resende <lresende@apache.org>

Closes apache#8774 from lresende/spark-10511.

(cherry picked from commit 1894653)
Signed-off-by: Sean Owen <sowen@cloudera.com>
(cherry picked from commit 4c4a9ba)

dev/create-release/release-build.sh

@@ -99,6 +99,7 @@ fi
 DEST_DIR_NAME="spark-$SPARK_PACKAGE_VERSION"
 USER_HOST="$ASF_USERNAME@people.apache.org"
 
+git clean -d -f -x
 rm .gitignore
 rm -rf .git
 cd ..