libfabric configury: make AC_CONFIG_FILES be unconditional

Also add the generated config.h file to .gitignore.

.gitignore

@@ -359,6 +359,7 @@ opal/include/opal/sys/powerpc/atomic-32.s
 opal/include/opal/sys/powerpc/atomic-64.s
 opal/include/opal/sys/powerpc/atomic-32-64.s
 opal/mca/base/mca_base_parse_paramfile_lex.c
+opal/mca/common/libfabric/libfabric/config.h
 opal/mca/btl/openib/btl_openib_lex.c
 opal/mca/btl/usnic/usnic_btl_run_tests
 opal/mca/crs/opal_crs.7

opal/mca/common/libfabric/configure.m4

@@ -18,6 +18,7 @@
 # ------------------------------------------------
 AC_DEFUN([MCA_opal_common_libfabric_CONFIG],[
     AC_CONFIG_FILES([opal/mca/common/libfabric/Makefile])
+    AC_CONFIG_HEADERS([opal/mca/common/libfabric/libfabric/config.h])
 
     # Initially state that we're unhappy
     opal_common_libfabric_happy=0
@@ -218,8 +219,6 @@ AC_DEFUN([_OPAL_COMMON_LIBFABRIC_SETUP_LIBFABRIC_EMBEDDED],[
                 [libfabric: do not build verbs provider])
             AC_DEFINE([HAVE_VERBS_DL], [0],
                 [libfabric: do not build verbs provider])
-
-            AC_CONFIG_HEADER([opal/mca/common/libfabric/libfabric/config.h])
            ])
 ])