Error message from indigo when trying open SMART format file with any Atom Generic and Pol

[AleksandraIvleva]

Steps to Reproduce

1. Execute /v2/indigo/convert with the following parameters (Pol in structure):
   {
   "struct": "\n Ketcher 9 62112292D 1 1.00000 0.00000 0\n\n 6 5 0 0 0 0 999 V2000\n 4.7250 -6.0750 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0\n 5.2250 -6.9410 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0\n 6.2250 -6.9410 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0\n 6.7250 -7.8071 0.0000 Pol 0 0 0 0 0 0 0 0 0 0 0 0\n 7.7250 -7.8071 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0\n 8.2250 -8.6731 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0\n 1 2 1 0 0 0\n 2 3 1 0 0 0\n 3 4 1 0 0 0\n 4 5 1 0 0 0\n 5 6 1 0 0 0\nM END\n",
   "output_format": "chemical/x-daylight-smarts",
   "options": {
   "smart-layout": true,
   "ignore-stereochemistry-errors": true,
   "mass-skip-error-on-pseudoatoms": false,
   "gross-formula-add-rsites": true,
   "gross-formula-add-isotopes": true
   }
   }
   Error message. Response:
   "IndigoException: SMILES saver: SMARTS format availble for query only"

2. Execute /v2/indigo/convert with the following parameters (the same structure as in Step1 + A):
   {
   "struct": "\n Ketcher 9 62112302D 1 1.00000 0.00000 0\n\n 6 5 0 0 0 0 999 V2000\n 4.7250 -6.0750 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0\n 5.2250 -6.9410 0.0000 A 0 0 0 0 0 0 0 0 0 0 0 0\n 6.2250 -6.9410 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0\n 6.7250 -7.8071 0.0000 Pol 0 0 0 0 0 0 0 0 0 0 0 0\n 7.7250 -7.8071 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0\n 8.2250 -8.6731 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0\n 1 2 1 0 0 0\n 2 3 1 0 0 0\n 3 4 1 0 0 0\n 4 5 1 0 0 0\n 5 6 1 0 0 0\nM END\n",
   "output_format": "chemical/x-daylight-smarts",
   "options": {
   "smart-layout": true,
   "ignore-stereochemistry-errors": true,
   "mass-skip-error-on-pseudoatoms": false,
   "gross-formula-add-rsites": true,
   "gross-formula-add-isotopes": true
   }
   }
   No error message. Response:

{
  "format": "chemical/x-daylight-smarts", 
  "struct": "[#6]-[!#1]-[#6]-[]-[#6]-[#6] |$;;;Pol;;$|"
}

3. Execute /v2/indigo/layout with parameters (struct from Step2):

{
  "struct": "[#6]-[!#1]-[#6]-[]-[#6]-[#6] |$;;;Pol;;$|",
  "output_format": "chemical/x-mdl-molfile",
  "options": {
    "smart-layout": true,
    "ignore-stereochemistry-errors": true,
    "mass-skip-error-on-pseudoatoms": false,
    "gross-formula-add-rsites": true
  }
}

Actual result: "error": "IndigoException: molecule auto loader: SMILES loader: empty atom?"

Expected result: If such structure is not supported we should show error message during Step2 call /convert (as in Step1), otherwise - calling /layout should not return error.

This issue can potentially be related: #463