requirements: Add 'decorator' dependency.

We already had this as an indirect dependency, but now it's going to be
needed to write a decorator for rate limiting authenticate() functions,
so it should be added to common.in.

requirements/common.in

@@ -173,3 +173,7 @@ yamole==2.1.6
 
 # Needed for string matching in AlertWordProcessor
 pyahocorasick==1.4.0
+
+# Needed for function decorators that don't break introspection.
+# Used for rate limiting authentication.
+decorator==4.4.0

requirements/dev.txt

@@ -45,7 +45,7 @@ cryptography==2.6.1       # via apns2, moto, pyopenssl, requests, service-identi
 cssselect==1.0.3          # via parsel, premailer, scrapy
 cssutils==1.0.2           # via premailer
 datetime==4.3             # via moto
-decorator==4.4.0          # via ipython, traitlets
+decorator==4.4.0
 defusedxml==0.6.0
 disposable-email-domains==0.0.52
 django-auth-ldap==2.0.0

requirements/prod.txt

@@ -30,7 +30,7 @@ chardet==3.0.4            # via requests
 cryptography==2.6.1       # via apns2, pyopenssl, requests
 cssselect==1.0.3          # via premailer
 cssutils==1.0.2           # via premailer
-decorator==4.4.0          # via ipython, traitlets
+decorator==4.4.0
 defusedxml==0.6.0
 disposable-email-domains==0.0.52
 django-auth-ldap==2.0.0