better work with SCLs

New in 7.0 version:

• RPM macros file works with SCLs, too.

• New convenience RPM macro %postgresql_module_requires.

• Simplified build against SCLs with --with-scl option.

• New test macro %postgresql_tests_run.

Incompatible changes in 7.0 version

• The %pgtest_init && %pgtest_start renamed to %postgresql_tests_init and
  %postgresql_tests_start.

security: CVE-2017-12172 CVE-2017-15097

• With configre --with-sysvinit we are able to install sysvinit
  configuration instead of systemd.

• For systemd systems, the "legacy" scripts for 'service postgresql initdb'
  and 'service postgresql upgrade' are installed.

New releases simplifying SCL build

• The rpm macro directory is automatically detected.

• the sysvinit/systemd systems are now detected

• properly compile and install postgresql-setup.1 man page

Version 5.0

• postgresql-setup --upgrade now works with "umask & 0004 != 0"
• Fixed semantics of 'redhat_sockets_hack' configuration option.
• The RPM macros file is installed automatically, it provides now
  %postgresql_major, %pgtests_init and %pgtests_start macros.
• Fixed automatic detection of $PGMAJORVERSION.