gnu: Remove needless inputs python-pip and python2-pip.

This is installed together with Python 3 anyway and for our build
of Python 2.

* gnu/packages/python.scm (python2-fixtures): [inputs] remove "python-pip".
* gnu/packages/pdf.scm (python2-reportlab): [native-inputs] remove
  "python2-pip". (python-reportlab)[properties]: remove "python2-variant".

gnu/packages/pdf.scm

@@ -650,14 +650,10 @@ using a stylus.")
     (description "This is the ReportLab PDF Toolkit.  It allows rapid creation
 of rich PDF documents, and also creation of charts in a variety of bitmap and
 vector formats.")
-    (license license:bsd-3)
-    (properties `((python2-variant . ,(delay python2-reportlab))))))
+    (license license:bsd-3)))
 
 (define-public python2-reportlab
-  (package
-    (inherit (package-with-python2
-              (strip-python2-variant python-reportlab)))
-    (native-inputs `(("python2-pip" ,python2-pip)))))
+  (package-with-python2 python-reportlab))
 
 (define-public impressive
   (package

gnu/packages/python.scm

@@ -2044,8 +2044,7 @@ and sensible default behaviors into your setuptools run.")
      `(("python-six" ,python-six)
        ("python-pbr-0.11" ,python-pbr-0.11)))
     (inputs
-     `(("python-pip" ,python-pip)
-       ;; Tests
+     `(;; Tests
        ("python-testtools" ,python-testtools)))
     (arguments
      '(#:tests? #f)) ; no setup.py test command