workaround for rgeos installation issue

Author: cpsievert

inst/docker/Dockerfile.vtest

@@ -93,11 +93,15 @@ RUN R -e "devtools::install_github('brodieG/diffobj@development')"
 ENV VDIFFR=true
 EXPOSE 3838
 
+# installing rgeos from CRAN is currently broken
+# http://r-sig-geo.2731867.n2.nabble.com/Re-Unexpected-configure-error-following-recent-rgeos-release-td7592423.html
+RUN R -e "install.packages('rgeos', repos='http://R-Forge.R-project.org', type='source')"
+
 # install any new dependencies, then either manage cases (the default) or run tests
 # note the workaround to get docker to run a proper exit status when there are testthat errors
 # https://github.com/r-lib/testthat/issues/515#issuecomment-304169376
 
-ENTRYPOINT R -e "devtools::install_deps('/home/plotly', dep = T); \
+CMD R -e "devtools::install_deps('/home/plotly', dep = T); \
   if (!identical(Sys.getenv('VMODE'), 'ci')) vdiffr::manage_cases('/home/plotly'); \
   res <- devtools::test('/home/plotly', reporter='summary'); \
   df <- as.data.frame(res); \