correct typo detected by Lee Hansen

Doc/lib/libbsddb.tex

@@ -129,7 +129,7 @@ keys in the file is unspecified, except in the case of B-Tree databases.
 \end{methoddesc}
 
 \begin{methoddesc}{previous}{}
-Set the cursor to the first item in the DB file and return it.  The
+Set the cursor to the previous item in the DB file and return it.  The
 order of keys in the file is unspecified, except in the case of B-Tree
 databases.  This is not supported on hashtable databases (those opened
 with \function{hashopen()}).