Enable readability-implicit-bool-conversion checks

These checks ensure that we're not implicitly converting ints or
pointers into bools, which makes the code easier to read.

Tested:
Ran series through redfish service validator.  No changes observed.
UUID failing in Qemu both before and after.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I1ca0be980d136bd4e5474341f4fd62f2f6bbdbae
diff --git a/.clang-tidy b/.clang-tidy
index 0027680..9958891 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -275,6 +275,7 @@
 readability-delete-null-pointer,
 readability-deleted-default,
 readability-else-after-return,
+readability-implicit-bool-conversion,
 readability-named-parameter,
 readability-redundant-control-flow,
 readability-redundant-declaration,