More robust parsing of changelog in build.xml

    <property name="rclib" value="${out.dir}/K9RemoteControl.jar" />

    <property name="rcdir" value="com/fsck/k9/remotecontrol/**" />

    <property name="changelog-path-src" value="res/xml/changelog_master.xml" />

    <condition property="android.executable" value="android.bat">

        <os family="windows" />

    </condition>

        </if.contrib>

        <echo>Setting version to ${version-name}</echo>

        <exec executable="perl" failonerror="true">

            <arg line="-0 -ne '/\x3Crelease version=\x22${version-name}\x22/ or die qq/No changelog for ${version-name}\n/' res/xml/changelog_master.xml" />

        <xpath

            input="${changelog-path-src}"

            expression="/changelog/release[@version='${version-name}']/@version"

            output="changelog-test" />

        <if.contrib>

            <equals arg1="${changelog-test}" arg2="${version-name}" />

            <else>

                <fail>No changelog for ${version-name}.</fail>

            </else>

        </if.contrib>

        <exec executable="git" failonerror="true" outputproperty="git-status" errorproperty="git-status-error">

            <arg line="status -s ${changelog-path-src}" />

        </exec>

        <if.contrib>

            <equals arg1="${git-status}" arg2="" />

            <else>

                <fail>Uncomitted changelog edits.</fail>

            </else>

        </if.contrib>

        <replace file="AndroidManifest.xml"

            token="android:versionName="${current-version-name}""

            value="android:versionName="${version-name}"" summary="true"

            <arg line="reset -q" />

        </exec>

        <exec executable="git" failonerror="true" outputproperty="git-ls-tree" errorproperty="git-ls-tree-error">

            <arg line="ls-tree ${git-branch-ref} res/xml/changelog_master.xml" />

            <arg line="ls-tree ${git-branch-ref} ${changelog-path-src}" />

        </exec>

        <regex property="changelog-path-dst" input="${git-branch-ref}" regexp=".*/([^/]+$)" select="changelog_\1_branch.xml" />

        <regex property="git-index-info" input="${git-ls-tree}" regexp="(.*\t).*" select="\1${changelog-path-dst}" />