Speed up git version retrieval by using jgit-describe.jar (Built from https://github.com/ShaneMcC/jgit-describe) to describe the git tag rather than shelling out.

Change-Id: I9953e39c0ee190123df09b5ca5afd8b0ef654f55
Reviewed-on: http://gerrit.dmdirc.com/2268
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Chris Smith <chris@dmdirc.com>

build-gitversion.xml

@@ -1,33 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project basedir=".">
-
-    <macrodef name="gitversion">
-        <attribute name="target"/>
-        <attribute name="outputproperty"/>
-        <attribute name="gitdir" default=".git"/>
-
-        <sequential>
-            <local name="lastcommit"/>
-
-            <exec executable="git" outputproperty="lastcommit">
-                <arg value="--git-dir"/>
-                <arg value="@{gitdir}"/>
-                <arg value="rev-list"/>
-                <arg value="--max-count=1"/>
-                <arg value="HEAD"/>
-                <arg value="--"/>
-                <arg value="@{target}"/>
-            </exec>
-
-            <exec executable="git" outputproperty="@{outputproperty}">
-                <arg value="--git-dir"/>
-                <arg value="@{gitdir}"/>
-                <arg value="describe"/>
-                <arg value="--tags"/>
-                <arg value="--always"/>
-                <arg value="${lastcommit}"/>
-            </exec>
-        </sequential>
-    </macrodef>
-
-</project>

build-versioning.xml

@@ -2,8 +2,6 @@
 <project name="DMDirc-versioning" default="default" basedir=".">
     <description>Adds automatic versioning information to DMDirc</description>
 
-    <include file="build-gitversion.xml"/>
-
     <property name="version.config" value="build/classes/com/dmdirc/version.config"/>
     <property name="defaults.path" value="modules/defaults/.git/"/>
     <property name="defaults.output" value="build/classes/com/dmdirc/config/defaults/"/>
@@ -11,6 +9,7 @@
     <property name="modealiases.target" value="${defaults.output}modealiases/generic"/>
 
     <available file=".git" property="is.git"/>
+    <taskdef name="git-describe" classname="org.mdonoughe.JGitDescribeTask" classpathref="libclasspath"/>
 
     <target name="-write-version" depends="-write-version-header, -add-version, -write-updater, -write-identities, -write-disable-updates"/>
 
@@ -86,8 +85,8 @@ identity:
     <target name="-read-identities" depends="-read-identities-git"/>
 
     <target name="-read-identities-git" if="is.git">
-        <gitversion target="default" gitdir="${defaults.path}" outputproperty="defaults.version"/>
-        <gitversion target="modealiases" gitdir="${defaults.path}" outputproperty="modealiases.version"/>
+        <git-describe dir="${defaults.path}" property="defaults.version" subdir="default" />
+        <git-describe dir="${defaults.path}" property="modealiases.version" subdir="modealiases" />
     </target>
 
 </project>