Pin dependency versions when using tools/venv.sh (#4629)

* Revert "Pin python-augeas version to avoid error with 1.0.0 (#4422)"

This reverts commit 1c51ae2588.

* make dependency-requirements

* separate certbot and dependency requirements

* fix build.py

* update hashin comment

* simplify release pinning

* separate letsencrypt dependency

* pin hashes in venv

* error out when bad things happen

* use pinned dependencies in tox

* Revert "pin hashes in venv"

This reverts commit 1cd38a9e50.

* use pip_install.sh in venv_common

* quote pip install args

* bump mock version

letsencrypt-auto-source/letsencrypt-auto

@@ -694,7 +694,7 @@ if [ "$1" = "--le-auto-phase2" ]; then
 
 # Hashin example:
 # pip install hashin
-# hashin -r letsencrypt-auto-requirements.txt cryptography==1.5.2
+# hashin -r dependency-requirements.txt cryptography==1.5.2
 # sets the new certbot-auto pinned version of cryptography to 1.5.2
 
 argparse==1.4.0 \
@@ -754,9 +754,9 @@ cryptography==1.5.3 \
 enum34==1.1.2 \
     --hash=sha256:2475d7fcddf5951e92ff546972758802de5260bf409319a9f1934e6bbc8b1dc7 \
     --hash=sha256:35907defb0f992b75ab7788f65fedc1cf20ffa22688e0e6f6f12afc06b3ea501
-funcsigs==0.4 \
-    --hash=sha256:ff5ad9e2f8d9e5d1e8bbfbcf47722ab527cf0d51caeeed9da6d0f40799383fde \
-    --hash=sha256:d83ce6df0b0ea6618700fe1db353526391a8a3ada1b7aba52fed7a61da772033
+funcsigs==1.0.2 \
+    --hash=sha256:330cc27ccbf7f1e992e69fef78261dc7c6569012cf397db8d3de0234e6c937ca \
+    --hash=sha256:a7bb0f2cf3a3fd1ab2732cb49eba4252c2af4240442415b4abce3b87022a8f50
 idna==2.0 \
     --hash=sha256:9b2fc50bd3c4ba306b9651b69411ef22026d4d8335b93afc2214cef1246ce707 \
     --hash=sha256:16199aad938b290f5be1057c0e1efc6546229391c23cea61ca940c115f7d3d3b
@@ -851,15 +851,21 @@ zope.interface==4.1.3 \
     --hash=sha256:928138365245a0e8869a5999fbcc2a45475a0a6ed52a494d60dbdc540335fedd \
     --hash=sha256:0d841ba1bb840eea0e6489dc5ecafa6125554971f53b5acb87764441e61bceba \
     --hash=sha256:b09c8c1d47b3531c400e0195697f1414a63221de6ef478598a4f1460f7d9a392
-mock==1.0.1 \
-    --hash=sha256:b839dd2d9c117c701430c149956918a423a9863b48b09c90e30a6013e7d2f44f \
-    --hash=sha256:8f83080daa249d036cbccfb8ae5cc6ff007b88d6d937521371afabe7b19badbc
+mock==2.0.0 \
+    --hash=sha256:5ce3c71c5545b472da17b72268978914d0252980348636840bd34a00b5cc96c1 \
+    --hash=sha256:b158b6df76edd239b8208d481dc46b6afd45a846b7812ff0ce58971cf5bc8bba
+
+# Contains the requirements for the letsencrypt package.
+#
+# Since the letsencrypt package depends on certbot and using pip with hashes
+# requires that all installed packages have hashes listed, this allows
+# dependency-requirements.txt to be used without requiring a hash for a
+# (potentially unreleased) Certbot package.
+
 letsencrypt==0.7.0 \
     --hash=sha256:105a5fb107e45bcd0722eb89696986dcf5f08a86a321d6aef25a0c7c63375ade \
     --hash=sha256:c36e532c486a7e92155ee09da54b436a3c420813ec1c590b98f635d924720de9
 
-# THE LINES BELOW ARE EDITED BY THE RELEASE SCRIPT; ADD ALL DEPENDENCIES ABOVE.
-
 acme==0.14.0 \
     --hash=sha256:fca8766a2596833e8886f7ef72cf82d1f6c6cffa895781a5676861c251b24b70 \
     --hash=sha256:ce7d2bca31e85adac1030c944e0a9d96e8b0f85cdc616b78d40eb09c91803543