Revert "Older python support"

This reverts commit 9d1d94536f40ba3ea3dc79f378a4a9a2469731b8.

Reworking to disable python PCP components for old python versions.
Revert "Older Python support ... some cases I missed earlier"

This reverts commit b87c3d801ad798e89ec189923e03fc180eee1a07.

Reworking to disable python PCP components for old python versions.
build: bring consistency to the various configure-enabled PMDAs

Use a common naming convention (that doesn't sometimes conflict
with build-system-wide settings) and use true/false explicitly,
like the build-system-wide yes/no options do.

Add the missing (commented-out) configure error check for PAPI,
and push the PAPI library setting (-lpapi) all the way through
into the PMDA makefile instead of dropping it part way.
build: disable builds of python components for pre-2.6 python

Revisit earlier python work to workaround problems in ancient
python versions.  Adds configure checking, makefile, packaging
and QA test work to ensure everything continues to function as
best it can (without python) on these older systems.