Corrected unit to addimentional unit cause bug in parameters

[sylvain_boyer6TGNB]

How to reproduce the error: 

#1 create user parameter openingRatio, set to 0.7  but leave the default unit in mm
==> create the user parameter with a 0.7mm value 

#2 click the user parameter unit and change to NO UNIT

==> the user parameter become (0.7mm)/mm

#3 create a second parameter ILength with unit in mm

#4 try to multiply openingRatio by ILength

Solution for now: delete the units manually in the openingRatio : "(0.7mm)/mm" to become "0.7"

Something in the unit check should be improved. Likely strings are being used as outputs.

[sylvain_boyer6TGNB]

Errata, the solution is to delete the openingRatio and recreate the user parameter with no units