Enable building with python by default in configure

Many tests in GPDB depend on plpython, hence enabling it by default is
helpful, instead of required to specify everytime. Given python is
needed on developer system for GPDB Management Scripts so its not
adding any new dependency.

Discussion:
https://groups.google.com/a/greenplum.org/g/gpdb-dev/c/laqc2YXxCWU/m/fS6ojeDIAQAJReviewed-by: NPaul Guo <guopa@vmware.com>

configure

@@ -1600,7 +1600,7 @@ Optional Packages:
   --with-tcl              build Tcl modules (PL/Tcl)
   --with-tclconfig=DIR    tclConfig.sh is in DIR
   --with-perl             build Perl modules (PL/Perl)
-  --with-python           build Python modules (PL/Python)
+  --without-python        build Python modules (PL/Python)
   --with-gssapi           build with GSSAPI support
   --with-krb-srvnam=NAME  default service principal name in Kerberos (GSSAPI)
                           [postgres]
@@ -8609,7 +8609,7 @@ if test "${with_python+set}" = set; then :
   esac
 
 else
-  with_python=no
+  with_python=yes
 
 fi
 

configure.in

@@ -893,7 +893,7 @@ AC_SUBST(with_perl)
 # Optionally build Python modules (PL/Python)
 #
 AC_MSG_CHECKING([whether to build Python modules])
-PGAC_ARG_BOOL(with, python, no, [build Python modules (PL/Python)])
+PGAC_ARG_BOOL(with, python, yes, [build Python modules (PL/Python)])
 AC_MSG_RESULT([$with_python])
 AC_SUBST(with_python)