dev-python/pypy3: fix gentoo-path.patch and rev bump

Test that install_path starts with '/usr/lib/pypy' instead of doing an
exact equality == test against the specific pypy version. This will
allow the patch to be reused between pypy and pypy3 without the risk of
having the gentoo specific fix fail to be detected due to a mismatched
pypy version number. This also prevents the need to maintain an exact
match the pypy version in the future since it will continue to change
and I assume there is also the possibility that both pypy3.6 and pypy3.7
might be installed on the same system at the same time.

Also rev bump so that users will recieve the fix.

This also removes a blocker for https://bugs.gentoo.org/729958 and
https://github.com/gentoo/gentoo/pull/16466.

Closes: https://bugs.gentoo.org/735140
Related-to: https://bugs.gentoo.org/729958
Signed-off-by: Tom Gillespie <tgbugs@gmail.com>
Closes: https://github.com/gentoo/gentoo/pull/16943
Signed-off-by: Michał Górny <mgorny@gentoo.org>

dev-python/pypy3/files/7.3.1-gentoo-path.patch

@@ -30,7 +30,7 @@ index 6fe62be..a4e9f0d 100644
          if (hasattr(sys, 'pypy_version_info') and
                  not name.endswith(('_user', '_home'))):
 -            if os.name == 'nt':
-+            if self.install_base == os.path.normpath('@EPREFIX@/usr/lib/pypy2.7'):
++            if self.install_base.startswith(os.path.normpath('@EPREFIX@/usr/lib/pypy')):
 +                # override paths for system-wide install
 +                name = 'gentoo'
 +            elif os.name == 'nt':