category field of importlog is being truncated

[sebbacon]

...so the category patient_list_size is coming out as patient_list_si.

This is breaking the logic that decides if it's time to re-run patient list size importing.

I did write a migration for this at some point, but it somehow seems to have been dropped (bad merge?)

[sebbacon]

This is the migration required:

# -*- coding: utf-8 -*-
# Generated by Django 1.9.1 on 2016-09-01 10:29
from __future__ import unicode_literals

from django.db import migrations, models

class Migration(migrations.Migration):

    dependencies = [
        ('frontend', '0006_importlog_populate'),
    ]

    operations = [
        migrations.AlterModelOptions(
            name='importlog',
            options={'ordering': ['-current_at']},
        ),
        migrations.AlterField(
            model_name='importlog',
            name='category',
            field=models.CharField(db_index=True, max_length=15),
        ),
    ]