etc/config.*/unset: unset FOAM_ETC

Patch contributed by Bruno Santos
Resolves bug-report http://bugs.openfoam.org/view.php?id=2285

etc/config.csh/unset

@@ -86,8 +86,9 @@ unsetenv WM_THIRD_PARTY_DIR
 
 unsetenv FOAM_APPBIN
 unsetenv FOAM_APP
-unsetenv FOAM_EXT_LIBBIN
 unsetenv FOAM_CODE_TEMPLATES
+unsetenv FOAM_ETC
+unsetenv FOAM_EXT_LIBBIN
 unsetenv FOAM_INST_DIR
 unsetenv FOAM_JOB_DIR
 unsetenv FOAM_LIBBIN

etc/config.sh/unset

@@ -77,8 +77,9 @@ unset WM_THIRD_PARTY_DIR
 
 unset FOAM_APPBIN
 unset FOAM_APP
-unset FOAM_EXT_LIBBIN
 unset FOAM_CODE_TEMPLATES
+unset FOAM_ETC
+unset FOAM_EXT_LIBBIN
 unset FOAM_INST_DIR
 unset FOAM_JOB_DIR
 unset FOAM_LIBBIN