fix travis

Author: matbesancon

.travis.yml

@@ -16,7 +16,7 @@ notifications:
 # uncomment the following lines to override the default test script
 script:
   - if [[ -a .git/shallow ]]; then git fetch --unshallow; fi
-  - julia -e 'using Pkg; Pkg.clone(pwd()); Pkg.build("GraphPlot"); Pkg.test("GraphPlot"; coverage=true)'
+  - julia -e 'using Pkg; Pkg.add("GraphPlot"); Pkg.test("GraphPlot"; coverage=true)'
 after_success:
   # push coverage results to Codecov
   - julia -e 'using Pkg; cd(Pkg.dir("GraphPlot")); Pkg.add("Coverage"); using Coverage; Codecov.submit(Codecov.process_folder())'