desc: Catch obvious sindex creation/dropping errors (#578)
table_variable_name: tbl
tests:

  - js: tbl.index_create("578", function(rec){return 1})
    py: tbl.index_create("578", lambda rec:1)
    rb: tbl.index_create("578") {|rec| 1}
    ot: {'created':1}
  - cd: tbl.index_wait("578").pluck('index', 'ready')
    ot: [{'ready':True, 'index':'578'}]

  - js: tbl.index_create("578", function(rec){return 1})
    py: tbl.index_create("578", lambda rec:1)
    rb: tbl.index_create("578") {|rec| 1}
    ot: err_regex("ReqlOpFailedError", "Index `578` already exists on table `[a-zA-Z0-9_]+.[a-zA-Z0-9_]+`[.]", [])

  - js: tbl.index_drop("578")
    py: tbl.index_drop("578")
    rb: tbl.index_drop("578")
    ot: {'dropped':1}

  - js: tbl.index_drop("578")
    py: tbl.index_drop("578")
    rb: tbl.index_drop("578")
    ot: err_regex("ReqlOpFailedError", "Index `578` does not exist on table `[a-zA-Z0-9_]+.[a-zA-Z0-9_]+`[.]", [])