tree-wide: yet another batch of coccinelle recommendations

Prettify certain parts of the codebase using coccinelle transformations
(no functional changes).

src/basic/memory-util.h

@@ -7,6 +7,7 @@
 #include <string.h>
 #include <sys/types.h>
 
+#include "alloc-util.h"
 #include "macro.h"
 
 size_t page_size(void) _pure_;
@@ -88,9 +89,7 @@ static inline void* erase_and_free(void *p) {
 
         l = malloc_usable_size(p);
         explicit_bzero_safe(p, l);
-        free(p);
-
-        return NULL;
+        return mfree(p);
 }
 
 static inline void erase_and_freep(void *p) {

src/basic/unit-name.c

@@ -621,7 +621,7 @@ int unit_name_mangle_with_suffix(const char *name, const char *operation, UnitNa
                         goto good;
                 log_full(flags & UNIT_NAME_MANGLE_WARN ? LOG_NOTICE : LOG_DEBUG,
                          "Glob pattern passed%s%s, but globs are not supported for this.",
-                         operation ? " " : "", operation ?: "");
+                         operation ? " " : "", strempty(operation));
                 suggest_escape = false;
         }