Fix SparkR package copy regex. The existing code leads to
```
Copying release tarballs to /home/****/public_html/spark-nightly/spark-branch-2.1-bin/spark-2.1.1-SNAPSHOT-2016_12_08_22_38-e8f351f9-bin
mput: SparkR-*: no files found
```

Author: Shivaram Venkataraman <shivaram@cs.berkeley.edu>

Closes #16231 from shivaram/typo-sparkr-build.

(cherry picked from commit be5fc6ef)
Signed-off-by: Shivaram Venkataraman <shivaram@cs.berkeley.edu>