RFR: 8048184 : (s) handle mercurial dev build version string

[Tim Bell]

Mike:

> Ping!
>
> (Still need a reviewer)

Looks good to me.  Approved.

TIm


> The pushed version will reduce the required Mercurial client version to 1.4 as that is the version that is shipped with Oracle Enterprise Linux and is used by a large number of our development/testing virtual machines. It's not convenient to update these systems to a newer version. Note that there are some reported reliability issues with Mercurial 1.4 and the current OpenJDK Mercurial servers. The failures do not involve any data-loss but it may be necessary to occasionally retry operations when using old client versions.
>
> Mike
>
> On Jun 26 2014, at 12:01 , Mike Duigou <mike.duigou at oracle.com> wrote:
>
>> Hello all;
>>
>> After pushing JDK-8047925 it was discovered that unofficial development builds of Mercurial use a different version string format and get_source.sh needs an enhancement to correctly parse this version string.
>>
>> I have also incorporated some cleanup suggested by Dave Pointon, made the script more defensive in it's handling of numeric values and replaced the use of 'which' with the more reliable 'command -v'
>>
>> jbsbug: https://bugs.openjdk.java.net/browse/JDK-8048184
>> webrev: http://cr.openjdk.java.net/~mduigou/JDK-8048184/0/webrev/
>>
>> Mike