Prepare for 1.11.1 release.

CHANGELOG.md

-# Changes in version 1.??.? - 2019-??-??
+# Changes in version 1.11.1 - 2019-09-19
 
  * Minor changes
    - Update create-tarballs.sh to also produce bridge pool assignments

build.xml

@@ -9,7 +9,7 @@
 
   <property name="javadoc-title" value="CollecTor API Documentation"/>
   <property name="implementation-title" value="CollecTor" />
-  <property name="release.version" value="1.11.0-dev" />
+  <property name="release.version" value="1.11.1" />
   <property name="project-main-class" value="org.torproject.metrics.collector.Main" />
   <property name="name" value="collector"/>
   <property name="metricslibversion" value="2.7.0" />