Fix startup syntax error

[wrefgtzweve]

Fixes the syntax error introduced in #3180

[wire] entities/gmod_wire_expression2/core/custom/prop.lua:1157: 'end' expected (to close 'function' at line 1150) near '__e2setcost'
  1. unknown - addons/wire/lua/entities/gmod_wire_expression2/core/extloader.lua:97
   2. pcall - [C]:-1
    3. e2_include_finalize - addons/wire/lua/entities/gmod_wire_expression2/core/extloader.lua:112
     4. unknown - addons/wire/lua/entities/gmod_wire_expression2/core/extloader.lua:185
      5. include - [C]:-1
       6. unknown - addons/wire/lua/entities/gmod_wire_expression2/core/init.lua:320
        7. include - [C]:-1
         8. unknown - addons/wire/lua/entities/gmod_wire_expression2/shared.lua:24
          9. include - [C]:-1
           10. unknown - addons/wire/lua/entities/gmod_wire_expression2/init.lua:3

There was an error loading the custom/prop.lua extension. Please report this to its developer.
attempt to call a nil value

[Denneisk]

Thank you.