After the execution of a job, the "Alternate settings file" build parameter is getting cleaned.

To reproduce the bug, follow the steps:

1. Create a new Maven2 job.
2. Fill in "Alternate settings file" for the job, and Maven targets "clean install" (Don't need a working project for compilation, the job will fail, but the bug is reproduced)
3. Execute the job
4. Reopen the job configuration. The "Alternate settings file" parameter is gone.

Obs.: With "Job Config History" plugin it is possible to view the change generated by SYSTEM to config file, removing the alternate settings parameter.

The first change after the creation shows the configuration of the alternateSettings parameter:
@@ -10,15 +11,18 @@
<blockBuildWhenUpstreamBuilding>false</blockBuildWhenUpstreamBuilding>
<triggers class="vector"/>
<concurrentBuild>false</concurrentBuild>
+ <goals>clean install</goals>
+ <alternateSettings>C:/jenkins-data/settings-alt.xml</alternateSettings>
<aggregatorStyleBuild>true</aggregatorStyleBuild>
<incrementalBuild>false</incrementalBuild>
<usePrivateRepository>false</usePrivateRepository>

After the job execution the parameter is gone:
@@ -12,18 +12,17 @@
<triggers class="vector"/>
<concurrentBuild>false</concurrentBuild>
<goals>clean install</goals>

• <alternateSettings>C:/jenkins-data/settings-alt.xml</alternateSettings>
  <aggregatorStyleBuild>true</aggregatorStyleBuild>
  <incrementalBuild>false</incrementalBuild>
  <usePrivateRepository>false</usePrivateRepository>