staging:17/tarballs: percona-gis-compat — no %elif (EL8 rpm 4.14)

The RockyLinux_8 build of da1e31c failed with
"error: line 75: Unknown tag: %elif 08 == 9": %elif landed in rpm 4.15, so
EL8's rpm 4.14 cannot parse it (RockyLinux_9 built fine). Rewrite the
per-base Provides block as nested %if/%else/%endif and note why.

No functional change: rpmspec -P still yields proj = 6.3.2 / gdal-libs =
3.0.4 on EL8, proj = 9.6.0 / gdal3.4-libs = 3.4.3 on EL9, and %{error} on
any other base.

Signed-off-by: Ricardo Dias <ricardo.dias@percona.com>

Author: rjd15372

root/ppg/staging/17/tarballs/percona-gis-compat/rpm/percona-gis-compat.spec

@@ -68,18 +68,22 @@ BuildArch:      noarch
 # percona-gdal/rpm/percona-gdal.spec (%%global gdal_version) for the same
 # base.  PostGIS carries a VERSIONED `Requires: gdal*-libs >= 3.0.4`, so a
 # Provides: below that floor would leave the chroot unresolvable.
+# Nested %%if/%%else rather than %%elif: EL8 ships rpm 4.14, which has no
+# %%elif (added in rpm 4.15, i.e. EL9) and fails with "Unknown tag: %%elif".
 %if 0%{?rhel} == 8
 # percona-proj 6.3.2, percona-gdal 3.0.4 on EL8.
 Provides:       proj = 6.3.2
 Provides:       gdal-libs = 3.0.4
-%elif 0%{?rhel} == 9
+%else
+%if 0%{?rhel} == 9
 # percona-proj 9.6.0, percona-gdal 3.4.3 on EL9.  The distro name is
 # gdal3.4-libs here (EPEL 9's compat GDAL for PostGIS).
 Provides:       proj = 9.6.0
 Provides:       gdal3.4-libs = 3.4.3
 %else
 %{error:percona-gis-compat: unsupported base (rhel=%{?rhel}); only EL8 and EL9 tarball chroots are defined}
 %endif
+%endif
 
 # The real runtimes this shim stands in for.
 Requires:       percona-gdal