Sbt and Maven builds pass on Linux boxes with encrypted folder

The contribution is my original work.  I license the work to the project under the project's open source license.

Building on a Linux box with encrypted home folder results in a failure.
```
[error] == Expanded type of tree ==
[error] 
[error] ConstantType(value = Constant(Throwable))
[error] 
[error] uncaught exception during compilation: java.io.IOException
[error] File name too long
[error] two errors found
```

This pull request fixes the problem in both the sbt and maven builds. 

Few other people are experiencing the same problem and will be good to be fixed.

http://apache-spark-user-list.1001560.n3.nabble.com/compiling-spark-source-code-td13980.html

http://mail-archives.apache.org/mod_mbox/spark-user/201312.mbox/%3C35F52C98-1178-480C-8D84-619D8F341D3E@gmail.com%3E