Update .travis.yml

Author: YingboMa

.travis.yml

@@ -12,6 +12,6 @@ notifications:
   email: false
 after_success:
   # push coverage results to Coveralls
-  - julia -e 'cd(Pkg.dir("RecursiveFactorization")); Pkg.add("Coverage"); using Coverage; Coveralls.submit(Coveralls.process_folder())'
+  - julia -e 'import Pkg; cd(Pkg.dir("RecursiveFactorization")); Pkg.add("Coverage"); using Coverage; Coveralls.submit(Coveralls.process_folder())'
   # push coverage results to Codecov
-  - julia -e 'cd(Pkg.dir("RecursiveFactorization")); Pkg.add("Coverage"); using Coverage; Codecov.submit(Codecov.process_folder())'
+  - julia -e 'import Pkg; cd(Pkg.dir("RecursiveFactorization")); Pkg.add("Coverage"); using Coverage; Codecov.submit(Codecov.process_folder())'