Fix test for Python to avoid error message

Getting error like
../../gnucash/configure: line 23573: x/opt/local/bin/python: No such file or directory

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@22946 57a11ea4-9604-0410-9ed3-97b8803252fd

configure.ac

@@ -1065,7 +1065,7 @@ then
 	   AC_MSG_ERROR([Could not find python >= 2.4. If you use --enable-python, you MUST have python installed!])
     ])
   AC_PYTHON_DEVEL(>= '2.4')
-  if [ "x${PYTHON}" = "x" ]
+  if test x${PYTHON} = "x"
   then
 	   AC_MSG_ERROR([Could not find Python development files. Make sure that the correct python-devel package is installed.])
   fi