Fix one more spelling typo

This commit was SVN r22156.

contrib/dist/linux/openmpi.spec

@@ -615,7 +615,7 @@ test "x$RPM_BUILD_ROOT" != "x" && rm -rf $RPM_BUILD_ROOT
 %if !%{sysconfdir_in_prefix}
 %{_sysconfdir}
 %endif
-# If %{instal_in_opt}, then we're instaling OMPI to
+# If %{install_in_opt}, then we're instaling OMPI to
 # /opt/openmpi/<version>.  But be sure to also explicitly mention
 # /opt/openmpi so that it can be removed by RPM when everything under
 # there is also removed.