Use the proper module directory

The stacklight module dir is /usr/share/lma_collector/common, not
/usr/share/lma_collector_modules. This fixes it.

linux/meta/heka.yml

     system:
       engine: sandbox
       module_file: /usr/share/lma_collector/decoders/generic_syslog.lua
-      module_dir: /usr/share/lma_collector_modules;/usr/share/heka/lua_modules
+      module_dir: /usr/share/lma_collector/common;/usr/share/heka/lua_modules
       config:
         syslog_pattern: '<%PRI%>%TIMESTAMP% %HOSTNAME% %syslogtag%%msg:::sp-if-no-1st-sp%%msg%\n'
         fallback_syslog_pattern: '%TIMESTAMP% %HOSTNAME% %syslogtag%%msg:::sp-if-no-1st-sp%%msg%\n'
     linux_hdd_errors:
       engine: sandbox
       module_file: /usr/share/lma_collector/filters/hdd_errors_counter.lua
-      module_dir: /usr/share/lma_collector_modules;/usr/share/heka/lua_modules
+      module_dir: /usr/share/lma_collector/common;/usr/share/heka/lua_modules
       preserve_data: false
       message_matcher: "Type == 'log' && Logger == 'system.kern'"
       ticker_interval: 10
     linux_logs_counter:
       engine: sandbox
       module_file: /usr/share/lma_collector/filters/logs_counter.lua
-      module_dir: /usr/share/lma_collector_modules;/usr/share/heka/lua_modules
+      module_dir: /usr/share/lma_collector/common;/usr/share/heka/lua_modules
       preserve_data: true
       message_matcher: "Type == 'log' && Logger =~ /^openstack\\\\./"
       ticker_interval: 1