docs: clean up empty element in db SVG

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@66068 15284696-431f-4ddb-bdfa-cd5b030d7da7

doc/grass_database.svg

@@ -272,17 +272,7 @@
          x="487.18951"
          y="495.54483"
          style="font-size:15px;stroke-width:4.43300009;stroke-miterlimit:4;stroke-dasharray:none">raster</tspan></text>
-    <flowRoot
-       xml:space="preserve"
-       id="flowRoot4190"
-       style="font-style:normal;font-weight:normal;font-size:40px;line-height:125%;font-family:Sans;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none;stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"><flowRegion
-         id="flowRegion4192"><rect
-           id="rect4194"
-           width="190.91884"
-           height="110.10663"
-           x="445.47726"
-           y="739.2149" /></flowRegion><flowPara
-         id="flowPara4196" /></flowRoot>    <text
+    <text
        xml:space="preserve"
        style="font-style:normal;font-weight:normal;font-size:10px;line-height:125%;font-family:Sans;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none;stroke-width:4.43300009;stroke-linecap:butt;stroke-linejoin:miter;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
        x="616.44299"