Remove old excludes
These are detected as errors since the clean up was done[1] in
the requirements repository. Minimum versions are bumped to avoid
installing known bad versions.
[1] 314734e938f107cbd5ebcc7af4d9167c11347406
Also remove the note about old pip's behavior because resolver in
recent pip does not require specific order.
Change-Id: I2606a494c60342b9849f8c837602dc81d28a5f95
diff --git a/doc/requirements.txt b/doc/requirements.txt
index 5f0bf6a..99f7e90 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -1,3 +1,3 @@
-sphinx!=1.6.6,!=1.6.7,>=1.6.2 # BSD
+sphinx>=1.7.0 # BSD
openstackdocstheme>=1.31.2 # Apache-2.0
reno>=2.5.0 # Apache-2.0