RFR: JDK-8174069 Verify that bash is at least version 3.2

[Magnus Ihse Bursie]

The build system uses features in make that was not present before 3.2. 
Bash 3.2 was released in 2007 so only very old systems is on 3.1 or 
older. However, we fail with strange error messages on such old systems, 
so we should check the version in configure.

Bug: https://bugs.openjdk.java.net/browse/JDK-8174069
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8174069-check-bash-version/webrev.01

/Magnus