webapp/latex/rnw: hide processing progress, just clutters error messages -- #2954
webapp/latex/rnw: hide processing progress, just clutters error messages -- #2954

sagemathinc/smc,DrXyzzy/smc,tscholl2/smc,tscholl2/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,DrXyzzy/smc,DrXyzzy/smc,sagemathinc/smc,sagemathinc/smc