Fix typo in commit de6fd1c8.

Per buildfarm members mandrill and hornet.

src/template/aix

@@ -15,7 +15,7 @@ fi
 # "IBM XL C/C++ for AIX, V12.1" miscompiles, for 32-bit, some inline
 # expansions of ginCompareItemPointers() "long long" arithmetic.  To
 # take advantage of inlining, build a 64-bit PostgreSQL.
-test "$GCC" != yes -a $(getconf HARDWARE_BITMODE) == '32'; then
+if test "$GCC" != yes -a $(getconf HARDWARE_BITMODE) == '32'; then
   echo "$as_me: WARNING: disabling inlining on 32 bit aix due to a bug in xlc" 2>&1
   CPPFLAGS="$CPPFLAGS -DPG_FORCE_DISABLE_INLINE"
 fi