report: indexed error message added to report emails

report: indexed error message added to report emails

Report emails will contain error message index now.
Index assigned to error message is described at the end of report.

sample:
avf-dot1q-l2bdbasemaclrn-eth-2memif-1dcr                               25ge2p1xxv710  64b   2t1c[0] 4t2c[0] 8t4c[0]

Legend:

[0] - Failed to run 'cli_inband clear runtime' PAPI command on host xxx.xxx.xxx.xxx

Signed-off-by: Viliam Luc <vluc@cisco.com>
Change-Id: I6c71eb8a8767827e18f88a9a1142b899158a190c
(cherry picked from commit 03bf0dd6ea67ef2b1386733d0b2ce3489c6a7f3e)