Revert "install macports from source"

This reverts commit 564bd00f.

(useless)

.travis.yml

@@ -109,11 +109,11 @@ install:
 # macports related stuff
   - if test -n "$PLUMED_MACPORTS" ; then export COLUMNS=80 ; fi
 # install macports from source:
-  - if test -n "$PLUMED_MACPORTS" ; then wget https://distfiles.macports.org/MacPorts/MacPorts-2.3.4.tar.bz2 && tar xvfj MacPorts-2.3.4.tar.bz2 ; fi
-  - if test -n "$PLUMED_MACPORTS" ; then cd MacPorts-2.3.4 && ./configure && sudo make install && cd - && sudo rm -fr MacPorts-2.3.4 ; fi
-# install macports from binary (faster, but have some trouble):
-#   - if test -n "$PLUMED_MACPORTS" ; then wget https://distfiles.macports.org/MacPorts/MacPorts-2.3.4-10.11-ElCapitan.pkg ; fi
-#   - if test -n "$PLUMED_MACPORTS" ; then sudo installer -pkg MacPorts-2.3.4-10.11-ElCapitan.pkg -target / ; fi
+#  - if test -n "$PLUMED_MACPORTS" ; then wget https://distfiles.macports.org/MacPorts/MacPorts-2.3.4.tar.bz2 && tar xvfj MacPorts-2.3.4.tar.bz2 ; fi
+#  - if test -n "$PLUMED_MACPORTS" ; then cd MacPorts-2.3.4 && ./configure && sudo make install && cd - && sudo rm -fr MacPorts-2.3.4 ; fi
+# install macports from binary (faster):
+  - if test -n "$PLUMED_MACPORTS" ; then wget https://distfiles.macports.org/MacPorts/MacPorts-2.3.4-10.11-ElCapitan.pkg ; fi
+  - if test -n "$PLUMED_MACPORTS" ; then sudo installer -pkg MacPorts-2.3.4-10.11-ElCapitan.pkg -target / ; fi
   - if test -n "$PLUMED_MACPORTS" ; then export PATH=/opt/local/bin:$PATH ; fi
   - if test -n "$PLUMED_MACPORTS" ; then sudo port -v selfupdate ; fi
   - if test -n "$PLUMED_MACPORTS" ; then make macports ; fi