c7000: add_blade_bmc_admins fails if no blades

[lero]

WARN[0007] Setup resource returned errors.               Error="\nHPE BladeSystem Onboard Administrator\n(C) Copyright 2006-2018 Hewlett Packard Enterprise Development LP\n\nOA-A45D36FD9CFB [SCRIPT MODE]> HPONCFG all  << end_marker\n\n\nBay 1: The blade is not present.\nBay 2: The blade is not present.\nBay 3: The blade is not present.\nBay 4: The blade is not present.\nBay 5: The blade is not present.\nBay 6: The blade is not present.\nBay 7: The blade is not present.\nBay 8: The blade is not present.\nBay 9: The blade is not present.\nBay 10: The blade is not present.\nBay 11: The blade is not present.\nBay 12: The blade is not present.\nBay 13: The blade is not present.\nBay 14: The blade is not present.\nBay 15: The blade is not present.\nBay 16: The blade is not present.\n\n\n<!-- ======== NO RIBCL RESULTS FOUND ======== -->\n\n\nOA-A45D36FD9CFB [SCRIPT MODE]> \n\nHPONCFG all  << end_marker\n<RIBCL VERSION=\"2.0\">\n<LOGIN USER_LOGIN=\"Administrator\" PASSWORD=\"">\n <USER_INFO MODE=\"write\">\n   <ADD_USER\n     USER_NAME=\"Administrator\"\n     USER_LOGIN=\"Administrator\"\n     PASSWORD=\"">\n     <ADMIN_PRIV value =\"Yes\"/>\n     <REMOTE_CONS_PRIV value =\"Yes\"/>\n     <RESET_SERVER_PRIV value =\"Yes\"/>\n     <VIRTUAL_MEDIA_PRIV value =\"Yes\"/>\n     <CONFIG_ILO_PRIV value=\"Yes\"/>\n   </ADD_USER>\n </USER_INFO>\n </LOGIN>\n</RIBCL>\nend_marker\n" IPAddress=10.194.84.49 Model="BladeSystem c7000 DDR2 Onboard Administrator with KVM" Serial=cz3 Vendor=HP resource=add_blade_bmc_admins
INFO[0011] Chassis setup actions done.                   IPAddress=10.194.84.49 Model="BladeSystem c7000 DDR2 Onboard Administrator with KVM" Serial=cz3 Vendor=HP applied="remove_blade_bmc_users, dynamicpower, bladespower" unsuccessful=