Git repositories might not be indexed correctly on older git versions (<1.8.4.3) when they have no 'master' branch and multiple branches pointing at remote/HEAD

When indexing a git repository using a git version older than 1.8.4.3, that contains no 'master' branch and has multiple branches pointing at remote/HEAD, you might see the following indexing error:

com.atlassian.fisheye.dvcs.handler.DvcsProcessException: Error while communicating with VCS: fatal: bad revision ^master 

Workarounds include creating a dummy 'master' branch, or upgrading git to a newer version.