Master doesn't compile with JDK 1.7

[Shameera Rathnayaka]

Hi Dev,

I just try to build the master with JDK 1.7 and got a compilation error,
This commit cb6c4ccf267c165e64d6858584b2300eaaa37df4
<https://github.com/apache/airavata/commit/cb6c4ccf267c165e64d6858584b2300eaaa37df4>
make master only build with JDK 1.8 as it use Long.BYTES which is comes
with JDK 1.8. Are we planning to move to 1.8 from next release?

Thanks,
Shameera.