Fix frozen string concatenation by indicating that it's mutable
Fix frozen string concatenation by indicating that it's mutable

References 89bcca5

yalab/rails,illacceptanything/illacceptanything,fabianoleittes/rails,betesh/rails,jeremy/rails,arunagw/rails,deraru/rails,eileencodes/rails,betesh/rails,georgeclaghorn/rails,gfvcastro/rails,rafaelfranca/omg-rails,starknx/rails,EmmaB/rails-1,Envek/rails,palkan/rails,eileencodes/rails,BlakeWilliams/rails,kddeisz/rails,joonyou/rails,tjschuck/rails,bogdanvlviv/rails,joonyou/rails,Vasfed/rails,iainbeeston/rails,Erol/rails,mechanicles/rails,gauravtiwari/rails,mohitnatoo/rails,untidy-hair/rails,Edouard-chin/rails,kmcphillips/rails,assain/rails,starknx/rails,illacceptanything/illacceptanything,gfvcastro/rails,vipulnsward/rails,Envek/rails,eileencodes/rails,tgxworld/rails,kddeisz/rails,utilum/rails,palkan/rails,kddeisz/rails,Stellenticket/rails,vipulnsward/rails,illacceptanything/illacceptanything,yahonda/rails,tjschuck/rails,kddeisz/rails,iainbeeston/rails,pvalena/rails,schuetzm/rails,Edouard-chin/rails,yalab/rails,eileencodes/rails,yawboakye/rails,aditya-kapoor/rails,pvalena/rails,assain/rails,betesh/rails,vipulnsward/rails,georgeclaghorn/rails,Stellenticket/rails,jeremy/rails,notapatch/rails,illacceptanything/illacceptanything,flanger001/rails,shioyama/rails,schuetzm/rails,schuetzm/rails,pvalena/rails,rafaelfranca/omg-rails,joonyou/rails,MSP-Greg/rails,Vasfed/rails,esparta/rails,shioyama/rails,illacceptanything/illacceptanything,tgxworld/rails,lcreid/rails,Edouard-chin/rails,lcreid/rails,Envek/rails,BlakeWilliams/rails,mechanicles/rails,assain/rails,untidy-hair/rails,aditya-kapoor/rails,MSP-Greg/rails,printercu/rails,starknx/rails,MSP-Greg/rails,georgeclaghorn/rails,gfvcastro/rails,arunagw/rails,BlakeWilliams/rails,prathamesh-sonpatki/rails,yhirano55/rails,illacceptanything/illacceptanything,baerjam/rails,untidy-hair/rails,georgeclaghorn/rails,fabianoleittes/rails,printercu/rails,EmmaB/rails-1,iainbeeston/rails,aditya-kapoor/rails,rafaelfranca/omg-rails,travisofthenorth/rails,prathamesh-sonpatki/rails,vipulnsward/rails,tgxworld/rails,flanger001/rails,gauravtiwari/rails,illacceptanything/illacceptanything,rails/rails,travisofthenorth/rails,baerjam/rails,kmcphillips/rails,rails/rails,Vasfed/rails,illacceptanything/illacceptanything,EmmaB/rails-1,flanger001/rails,tgxworld/rails,travisofthenorth/rails,Edouard-chin/rails,illacceptanything/illacceptanything,gauravtiwari/rails,repinel/rails,printercu/rails,kmcphillips/rails,Stellenticket/rails,jeremy/rails,yhirano55/rails,lcreid/rails,travisofthenorth/rails,yhirano55/rails,mohitnatoo/rails,deraru/rails,esparta/rails,jeremy/rails,deraru/rails,notapatch/rails,baerjam/rails,illacceptanything/illacceptanything,bogdanvlviv/rails,mohitnatoo/rails,yalab/rails,illacceptanything/illacceptanything,shioyama/rails,yalab/rails,illacceptanything/illacceptanything,gfvcastro/rails,Stellenticket/rails,rails/rails,repinel/rails,betesh/rails,kmcphillips/rails,esparta/rails,yahonda/rails,pvalena/rails,fabianoleittes/rails,MSP-Greg/rails,yawboakye/rails,baerjam/rails,lcreid/rails,assain/rails,schuetzm/rails,iainbeeston/rails,tjschuck/rails,mechanicles/rails,BlakeWilliams/rails,prathamesh-sonpatki/rails,fabianoleittes/rails,untidy-hair/rails,mechanicles/rails,deraru/rails,printercu/rails,illacceptanything/illacceptanything,Erol/rails,utilum/rails,repinel/rails,palkan/rails,yawboakye/rails,arunagw/rails,flanger001/rails,joonyou/rails,esparta/rails,Erol/rails,palkan/rails,aditya-kapoor/rails,illacceptanything/illacceptanything,notapatch/rails,mohitnatoo/rails,yahonda/rails,utilum/rails,bogdanvlviv/rails,tjschuck/rails,utilum/rails,repinel/rails,arunagw/rails,notapatch/rails,Envek/rails,yahonda/rails,bogdanvlviv/rails,Vasfed/rails,yhirano55/rails,prathamesh-sonpatki/rails,yawboakye/rails,Erol/rails,shioyama/rails,rails/rails,illacceptanything/illacceptanything