Remove redundant requires

* lisp/gnus/canlock.el (sha1):
* lisp/international/utf7.el (base64):
* lisp/net/hmac-md5.el (md5):
* lisp/org/ob-processing.el (sha1):
* lisp/org/org-feed.el (sha1):
* test/lisp/net/rfc2104-tests.el (sha1, md5): Don't require features
that are built-in, and always provided.

lisp/gnus/canlock.el

@@ -41,8 +41,6 @@
 
 ;;; Code:
 
-(require 'sha1)
-
 (defvar mail-header-separator)
 
 (defgroup canlock nil

lisp/international/utf7.el

@@ -63,7 +63,6 @@
 
 ;;; Code:
 
-(require 'base64)
 (require 'mm-util)
 
 (defconst utf7-direct-encoding-chars " -%'-*,-[]-}"

lisp/net/hmac-md5.el

@@ -29,7 +29,6 @@
 
 (eval-when-compile (require 'hmac-def))
 (require 'hex-util)			; (decode-hex-string STRING)
-(require 'md5)				; expects (md5 STRING)
 
 (defun md5-binary (string)
   "Return the MD5 of STRING in binary form."

lisp/org/ob-processing.el

@@ -56,7 +56,6 @@
 (org-assert-version)
 
 (require 'ob)
-(require 'sha1)
 
 (declare-function processing-sketch-run "ext:processing-mode" ())
 

lisp/org/org-feed.el

@@ -92,7 +92,6 @@
 (org-assert-version)
 
 (require 'org)
-(require 'sha1)
 
 (declare-function url-retrieve-synchronously "url"
                   (url &optional silent inhibit-cookies timeout))

test/lisp/net/rfc2104-tests.el

@@ -23,8 +23,6 @@
 
 (require 'ert)
 (require 'rfc2104)
-(require 'sha1)
-(require 'md5)
 
 (ert-deftest dbus-test-sha1 ()
   (should