Building controller from scratch yields the following error:
[INFO] Scanning for projects...
[ERROR] The build could not read 1 project -> [Help 1]
[ERROR]
[ERROR] The project org.opendaylight.controller:opendaylight-karaf-empty:1.5.0-SNAPSHOT (/home/csd/odlbuildnew/c2/karaf/opendaylight-karaf-empty/pom.xml) has 1 error
[ERROR] Non-resolvable parent POM: Could not find artifact org.opendaylight.controller:karaf-parent:pom:1.5.0-SNAPSHOT and 'parent.relativePath' points at no local POM @ line 3, column 11 -> [Help 2]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/ProjectBuildingException
[ERROR] [Help 2] http://cwiki.apache.org/confluence/display/MAVEN/UnresolvableModelException

which is a missing dependency. If I go into karaf/karaf-parent and run "mv clean install" in there first, then the controller build succeeds.
Just don't know enough about pom files to fix myself. This seems to have been triggered by this commit:
commit c0df5742e4352be1fc5c382055149556ecb9f0a0
Author: Ed Warnicke <eaw@cisco.com>
Date: Mon Mar 2 10:05:49 2015 -0800

Switch opendaylight-karaf-empty to using karaf-parent

This is important to make sure the correct piece are in place to
use opendaylight-karaf-empty as a basis for karaf integration tests.

Change-Id: I404b78bb9a46162b0393d495bc5d46977e2140a9
Signed-off-by: Ed Warnicke <eaw@cisco.com>