config-gerrit: Remove link to removed 'database' section
config-gerrit: Remove link to removed 'database' section

The "[[database]]" section was removed in change I6963ee23a, but
there is still a hyperlink to it which results in a warning when
building the documentation:

  WARNING: invalid reference: database

Remove the sentence with the link.

Change-Id: I54bdf467859d82d5a75b6295d542c8e8c30c88de

GerritCodeReview/gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit