Mail handler throws exception: Minimum abbreviation width is 4

Summary

When the jira.text.field.character.limit is set to 0, this breaks Service Desk Mail Handler when processing emails to create issues.

Environment

JSD 3.1.1

Steps to Reproduce

1. Navigate through JIRA Administration Menu > System > Advanced Settings, set the advanced setting parameter jira.text.field.character.limit to 0.
2. Configure Service Desk Email Channel to create issues.

Expected Results

Issues are created from email with unlimited text character limits.

Actual Results

1. No issues are created via Service Desk Email Channel
2. The following is thrown in the atlassian-jira-incoming-mail.log

   2016-03-10 22:25:41,641 ERROR [] Caesium-1-1 anonymous     Exception when MailHandlerWorker handles message: 
   java.lang.IllegalArgumentException: Minimum abbreviation width is 4
   	at org.apache.commons.lang.StringUtils.abbreviate(StringUtils.java:5920) [commons-lang-2.6.jar:2.6]
   ...
   at com.atlassian.servicedesk.internal.feature.emailchannel.EmailUtil.processMessageBody(EmailUtil.java:60) [?:?]
   	at com.atlassian.servicedesk.internal.feature.emailchannel.IncomingEmailParser.parse(IncomingEmailParser.java:60) [?:?]
   	at com.atlassian.servicedesk.internal.feature.emailchannel.IncomingEmailManager.createIssueInJiraContext(IncomingEmailManager.scala:190) [?:?]