Do not use enum's hashCode() value.

A use of enum's hashCode() may break InfiniSpan consistency because
its hash code in a JVM differs from value in another JVM.

Other changes:

  * checkstyle: Allow use of magic number in hashCode().

Change-Id: I54d7e6e2503f617a89379a3cc81cc3fc492af8cb
Signed-off-by: Shigeru Yasuda <s-yasuda@da.jp.nec.com>