Watcher: Remove build based property creation (elastic/elasticsearch#2107)

There we still left over files from the clean up PR to not use
build properties for the watcher templates.

Relates elastic/elasticsearch#2040

Original commit: elastic/x-pack-elasticsearch@b838d92124

elasticsearch/x-pack/build.gradle

@@ -70,8 +70,6 @@ compileTestJava.options.compilerArgs << "-Xlint:-deprecation,-rawtypes,-serial,-
 
 ext.expansions = [
   'project.version': version,
-  // Used in watcher index templates
-  'xpack.watcher.template.version': '1',
 ]
 
 processResources {

elasticsearch/x-pack/watcher/src/main/resources/watcher.properties

@@ -1 +0,0 @@
-xpack.watcher.template.version=${xpack.watcher.template.version}