Do not add quotes around SRC_PATH, the quoting has to be done at a later

stage else the quotes may appear in the middle of a path if it is
constructed with SRC_PATH.

Originally committed as revision 5010 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -1892,7 +1892,7 @@ if test "$source_path_used" = "yes" ; then
     done
     echo "SRC_PATH=$source_path" >> config.mak
 else
-    echo "SRC_PATH='$source_path'" >> config.mak
+    echo "SRC_PATH=$source_path" >> config.mak
 fi
 
 if test "$amr_wb" = "yes" ; then