Use LocationMatch to cache zuul api statuses

We need a regex to match the url path for zuul statuses. Our existing
setup assumed this would work in a CacheEnable directive but it seems
that it does not. Move this into a LocationMatch which explicitly
supports regexes.

Change-Id: I9df06d2af31ce6550e537f4594640487cca1d735

playbooks/roles/zuul-web/templates/zuul.vhost.j2

@@ -56,7 +56,9 @@ LogFormat "%h %l %u [%{%F %T}t.%{msec_frac}t] \"%r\" %>s %b %{cache-status}e \"%
     CacheDefaultExpire 5
     <IfModule mod_mem_cache.c>
       # TODO: Should we cache the rest of the API too?
-      CacheEnable mem /api/tenant/.*/status
+      <LocationMatch "^/api/tenant/.*/status">
+        CacheEnable mem
+      </LocationMatch>
       CacheEnable mem /static/
       # 80MB max cache size. 10 objects at 8MB max each.
       MCacheSize 81920
@@ -67,7 +69,9 @@ LogFormat "%h %l %u [%{%F %T}t.%{msec_frac}t] \"%r\" %>s %b %{cache-status}e \"%
       MCacheMaxStreamingBuffer 8388608
     </IfModule>
     <IfModule mod_cache_disk.c>
-      CacheEnable disk /api/tenant/.*/status
+      <LocationMatch "^/api/tenant/.*/status">
+        CacheEnable disk
+      </LocationMatch>
       CacheEnable disk /static/
       CacheRoot /var/cache/apache2/mod_cache_disk
       CacheMaxFileSize 10000000