Fix bug in Piecewise._eval_interval
Fix bug in Piecewise._eval_interval

- now has a consistent return form

aktech/sympy,Mitchkoens/sympy,skirpichev/omg,kevalds51/sympy,yashsharan/sympy,asm666/sympy,ga7g08/sympy,Vishluck/sympy,asm666/sympy,toolforger/sympy,jerli/sympy,kaushik94/sympy,dqnykamp/sympy,jaimahajan1997/sympy,Shaswat27/sympy,oliverlee/sympy,mafiya69/sympy,atreyv/sympy,kevalds51/sympy,grevutiu-gabriel/sympy,Designist/sympy,iamutkarshtiwari/sympy,MechCoder/sympy,maniteja123/sympy,dqnykamp/sympy,souravsingh/sympy,jbbskinny/sympy,yashsharan/sympy,Titan-C/sympy,bukzor/sympy,abloomston/sympy,jamesblunt/sympy,debugger22/sympy,wanglongqi/sympy,lindsayad/sympy,iamutkarshtiwari/sympy,Gadal/sympy,kaichogami/sympy,oliverlee/sympy,emon10005/sympy,madan96/sympy,MechCoder/sympy,sunny94/temp,Arafatk/sympy,MridulS/sympy,postvakje/sympy,kaichogami/sympy,mafiya69/sympy,vipulroxx/sympy,kaushik94/sympy,moble/sympy,rahuldan/sympy,Davidjohnwilson/sympy,hargup/sympy,atsao72/sympy,MechCoder/sympy,toolforger/sympy,ahhda/sympy,Designist/sympy,kumarkrishna/sympy,hargup/sympy,MridulS/sympy,postvakje/sympy,drufat/sympy,saurabhjn76/sympy,beni55/sympy,sampadsaha5/sympy,sampadsaha5/sympy,jamesblunt/sympy,vipulroxx/sympy,pandeyadarsh/sympy,meghana1995/sympy,souravsingh/sympy,aktech/sympy,sampadsaha5/sympy,shikil/sympy,ahhda/sympy,shikil/sympy,emon10005/sympy,yukoba/sympy,jaimahajan1997/sympy,pandeyadarsh/sympy,shipci/sympy,sahilshekhawat/sympy,garvitr/sympy,ChristinaZografou/sympy,sahmed95/sympy,cccfran/sympy,Sumith1896/sympy,wanglongqi/sympy,Designist/sympy,moble/sympy,Mitchkoens/sympy,grevutiu-gabriel/sympy,madan96/sympy,VaibhavAgarwalVA/sympy,abloomston/sympy,oliverlee/sympy,farhaanbukhsh/sympy,kaichogami/sympy,skidzo/sympy,Curious72/sympy,yashsharan/sympy,debugger22/sympy,ga7g08/sympy,pbrady/sympy,maniteja123/sympy,wanglongqi/sympy,grevutiu-gabriel/sympy,skidzo/sympy,Arafatk/sympy,AkademieOlympia/sympy,shikil/sympy,dqnykamp/sympy,yukoba/sympy,AunShiLord/sympy,jerli/sympy,Curious72/sympy,AkademieOlympia/sympy,liangjiaxing/sympy,atsao72/sympy,Vishluck/sympy,saurabhjn76/sympy,iamutkarshtiwari/sympy,garvitr/sympy,diofant/diofant,garvitr/sympy,hrashk/sympy,VaibhavAgarwalVA/sympy,shipci/sympy,Curious72/sympy,cswiercz/sympy,vipulroxx/sympy,sahmed95/sympy,yukoba/sympy,wyom/sympy,rahuldan/sympy,Shaswat27/sympy,Davidjohnwilson/sympy,sahmed95/sympy,cccfran/sympy,Mitchkoens/sympy,AkademieOlympia/sympy,rahuldan/sympy,ChristinaZografou/sympy,maniteja123/sympy,pbrady/sympy,chaffra/sympy,cswiercz/sympy,jaimahajan1997/sympy,postvakje/sympy,Titan-C/sympy,cccfran/sympy,drufat/sympy,chaffra/sympy,mcdaniel67/sympy,aktech/sympy,jamesblunt/sympy,VaibhavAgarwalVA/sympy,Titan-C/sympy,ga7g08/sympy,farhaanbukhsh/sympy,Vishluck/sympy,sahilshekhawat/sympy,hrashk/sympy,kevalds51/sympy,souravsingh/sympy,shipci/sympy,abloomston/sympy,emon10005/sympy,Gadal/sympy,pandeyadarsh/sympy,liangjiaxing/sympy,atsao72/sympy,abhiii5459/sympy,wyom/sympy,wyom/sympy,abhiii5459/sympy,atreyv/sympy,Sumith1896/sympy,meghana1995/sympy,hargup/sympy,cswiercz/sympy,madan96/sympy,ChristinaZografou/sympy,mafiya69/sympy,beni55/sympy,Gadal/sympy,Davidjohnwilson/sympy,atreyv/sympy,asm666/sympy,jbbskinny/sympy,drufat/sympy,Arafatk/sympy,abhiii5459/sympy,lindsayad/sympy,liangjiaxing/sympy,AunShiLord/sympy,moble/sympy,skidzo/sympy,bukzor/sympy,kumarkrishna/sympy,kaushik94/sympy,chaffra/sympy,mcdaniel67/sympy,Shaswat27/sympy,mcdaniel67/sympy,debugger22/sympy,toolforger/sympy,jbbskinny/sympy,bukzor/sympy,MridulS/sympy,meghana1995/sympy,pbrady/sympy,sahilshekhawat/sympy,saurabhjn76/sympy,Sumith1896/sympy,lindsayad/sympy,sunny94/temp,AunShiLord/sympy,jerli/sympy,hrashk/sympy,beni55/sympy,sunny94/temp,kumarkrishna/sympy,farhaanbukhsh/sympy,ahhda/sympy