Document access to BRMS/BPMS maven repo due to already reported problems:
https://bugzilla.redhat.com/show_bug.cgi?id=1074986
https://bugzilla.redhat.com/show_bug.cgi?id=1059584

The solution is described here https://bugzilla.redhat.com/show_bug.cgi?id=1059584#c4

Pasting it also here:

"It is either needed to turn on pre-emptive authentication for the repository server by

    <server>
      <id>guvnor-m2-repo</id>
      <username>admin</username>
      <password>admin</password>
      <configuration>
        <wagonProvider>httpclient</wagonProvider>
        <httpConfiguration>
          <all>
            <usePreemptive>true</usePreemptive>
          </all>
        </httpConfiguration>
      </configuration>
    </server>

or set Authorization HTTP header with Base64 encoded credentials

    <server>
      <id>guvnor-m2-repo</id>
      <configuration>
        <httpHeaders>
          <property>
            <name>Authorization</name>
            <!-- Base64-encoded "admin:admin" -->
            <value>Basic YWRtaW46YWRtaW4=</value>
          </property>
        </httpHeaders>
      </configuration>
    </server>

This should be documented."