url update; USGS SRTM ftp data site has moved

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@49288 15284696-431f-4ddb-bdfa-cd5b030d7da7

scripts/r.in.srtm/r.in.srtm.html

@@ -4,7 +4,7 @@
 
 SRTM data sets can be downloaded from NASA at this FTP site (Version 1 and the
 improved Version 2):<br>
-<a href="ftp://e0srp01u.ecs.nasa.gov/srtm/">ftp://e0srp01u.ecs.nasa.gov/srtm/</a>
+<a href="http://dds.cr.usgs.gov/srtm/">http://dds.cr.usgs.gov/srtm/</a>
 
 <h2>NOTES</h2>