Fix regression.sh to work on OpenBSD which has md5 instead of md5sum

but it is in the path (/bin), not /sbin.

Originally committed as revision 16088 to svn://svn.ffmpeg.org/ffmpeg/trunk

tests/regression.sh

@@ -37,6 +37,8 @@ target_crcfile="$target_datadir/$this.crc"
 
 if [ X"`echo | md5sum 2> /dev/null`" != X ]; then
     do_md5sum() { md5sum -b $1; }
+elif [ X"`echo | md5 2> /dev/null`" != X ]; then
+    do_md5sum() { md5 -r $1 | sed 's# \**\./# *./#'; }
 elif [ -x /sbin/md5 ]; then
     do_md5sum() { /sbin/md5 -r $1 | sed 's# \**\./# *./#'; }
 else