Overhaul Spack's URL parsing (#2972)

* Remove fake URLs from Spack

* Ignore long lines for URLs that start with ftp:

* Preliminary changes to version regexes

* New redesign of version regexes

* Allow letters in version-only

* Fix detection of versions that end in Final

* Rearrange a few regexes and add examples

* Add tests for common download repositories

* Add test cases for common tarball naming schemes

* Finalize version regexes

* spack url test -> spack url summary

* Clean up comments

* Rearrange suffix checks

* Use query strings for name detection

* Remove no longer necessary url_for_version functions

* Strip off extraneous information after package name

* Add one more test

* Dot in square brackets does not need to be escaped

* Move renaming outside of parse_name_offset

* Fix versions for a couple more packages

* Fix flake8 and doc tests

* Correctly parse Python, Lua, and Bio++ package names

* Use effective URLs for mfem

* Add checksummed version to mitos

* Remove url_for_version from STAR-CCM+ package

* Revert changes to version numbers with underscores and dashes

* Fix name detection for tbb

* Correctly parse Ruby gems

* Reverted mfem back to shortened URLs.

* Updated instructions for better security

* Remove preferred=True from newest version

* Add tests for new `spack url list` flags

* Add tests for strip_name_suffixes

* Add unit tests for version separators

* Fix bugs related to parseable name but in parseable version

* Remove dead code, update docstring

* Ignore 'binary' at end of version string

* Remove platform from version

* Flip libedit version numbers

* Re-support weird NCO alpha/beta versions

* Rebase and remove one new fake URL

* Add / to beginning of regex to avoid picking up similarly named packages

* Ignore weird tar versions

* Fix bug in url parse --spider when no versions found

* Less strict version matching for spack versions

* Don't rename Python packages

* Be a little more selective, version must begin with a digit

* Re-add fake URLs

* Fix up several other packages

* Ignore more file endings

* Add parsing support for Miniconda

* Update tab completion

* XFAILS are now PASSES for 2 web tests

var/spack/repos/builtin/packages/scotch/package.py

@@ -31,8 +31,7 @@ class Scotch(Package):
        partitioning, graph clustering, and sparse matrix ordering."""
 
     homepage = "http://www.labri.fr/perso/pelegrin/scotch/"
-    url = "http://gforge.inria.fr/frs/download.php/latestfile/298/scotch_6.0.3.tar.gz"  # noqa: E501
-    base_url = "http://gforge.inria.fr/frs/download.php/latestfile/298"
+    url      = "http://gforge.inria.fr/frs/download.php/latestfile/298/scotch_6.0.4.tar.gz"
     list_url = "http://gforge.inria.fr/frs/?group_id=248"
 
     version('6.0.4', 'd58b825eb95e1db77efe8c6ff42d329f')
@@ -71,12 +70,10 @@ class Scotch(Package):
     # from the Scotch hosting site.  These alternative archives include a
     # superset of the behavior in their default counterparts, so we choose to
     # always grab these versions for older Scotch versions for simplicity.
-    def url_for_version(self, version):
-        return super(Scotch, self).url_for_version(version)
-
     @when('@:6.0.0')
     def url_for_version(self, version):
-        return '%s/scotch_%s_esmumps.tar.gz' % (Scotch.base_url, version)
+        url = "http://gforge.inria.fr/frs/download.php/latestfile/298/scotch_{0}_esmumps.tar.gz"
+        return url.format(version)
 
     def patch(self):
         self.configure()