Ganglia GPU Monitoring Enhancements

Metrics Added:
* ‘_ecc_db_error’ : Double Bit ECC Error.
* ‘_ecc_sb_error’ : Single Bit ECC Error.
* ‘_power_violation_report’ : GPU Power violation.
* ‘_encoder_util’ : Encoder Utilization.
* ‘_decoder_util’ : Decoder Utilization.
* ‘_bar1_memory’ : Bar1 Memory.
* ‘_shutdown_temp’ : Shutdown Temperature.
* ‘_slowdown_temp’: Slowdown Temperature.

Metrics Modified:
* ‘_graphics_speed’ to ‘graphics_clock_report’. Reason:  Changed ‘speed’ to ‘clock’ for better meaningful name. Added ‘_report’ for custom php graph file support.
* ‘_sm_speed’ to ‘_sm_clock_report’. Reason: same as above.
* ‘_mem_speed’ to ‘_mem_clock_report’. Reason: same as above.
* ‘_mem_used’ to ‘_fb_memory’. Rason: match with NVML and eliminate ambiguity between ‘Frame Buffer Memory’ and ‘Bar1 Memory’.
* ‘_power_usage’ to ‘_power_usage_report’. Reason: custom php graph file support.
* ‘_max_graphics_speed’ to ‘_max_graphics_clock’. Reason: Changed ‘speed’ to ‘clock’ for better meaningful name.
* ‘_max_sm_speed’ to ‘_max_sm_clock’. Reason: as above.
* ‘_max_mem_speed’ to ‘_max_mem_clock’. Reason: as above.
* Moved ‘_max*’ metrics from graph to top constant metrics section(host overview).

Metrics Deleted:
* power_man_mode.
* perf_state.

Custom Graph Modifications:

* Clear old php graph files which wasn’t working.
* Generalization of No# Of GPUs for which custom graphs can be supported. Now, single php file can render custom graph for each GPU#. This requires the modification on ganglia-web module, which has been done as a separate pull request.
* Added Max line on some graphs to provide better overview of limit/usage ratio.