fix heap use after free when checking Safari version (OS X)
fix heap use after free when checking Safari version (OS X)

jar1karp/rstudio,piersharding/rstudio,JanMarvin/rstudio,jar1karp/rstudio,JanMarvin/rstudio,jrnold/rstudio,piersharding/rstudio,JanMarvin/rstudio,jar1karp/rstudio,jar1karp/rstudio,jrnold/rstudio,piersharding/rstudio,piersharding/rstudio,JanMarvin/rstudio,JanMarvin/rstudio,JanMarvin/rstudio,piersharding/rstudio,JanMarvin/rstudio,piersharding/rstudio,piersharding/rstudio,piersharding/rstudio,jrnold/rstudio,jar1karp/rstudio,jar1karp/rstudio,jar1karp/rstudio,JanMarvin/rstudio,jrnold/rstudio,jar1karp/rstudio,JanMarvin/rstudio,jrnold/rstudio,jrnold/rstudio,jrnold/rstudio,jar1karp/rstudio,jrnold/rstudio,piersharding/rstudio,jrnold/rstudio