packagefs: Use "pkgfs" in object cache names.

Makes the "slabs" KDL command output align better.

src/add-ons/kernel/file_systems/packagefs/kernel_interface.cpp

@@ -1081,7 +1081,7 @@ packagefs_std_ops(int32 op, ...)
 			}
 
 			PackageFileHeapAccessorBase::sChunkCache =
-				create_object_cache_etc("packagefs heap buffers",
+				create_object_cache_etc("pkgfs heap buffers",
 					PackageFileHeapAccessorBase::kChunkSize, sizeof(void*),
 					0, /* magazine capacity, count */ 2, 1, 0, NULL,
 					NULL, NULL, NULL);

src/add-ons/kernel/file_systems/packagefs/util/ClassCache.h

@@ -18,7 +18,7 @@
 		if (size != sizeof(CLASS)) \
 			panic("unexpected size passed to operator new!"); \
 		if (s##CLASS##Cache == NULL) { \
-			s##CLASS##Cache = create_object_cache("packagefs " #CLASS "s", \
+			s##CLASS##Cache = create_object_cache("pkgfs " #CLASS "s", \
 				sizeof(CLASS), 8, NULL, NULL, NULL); \
 		} \
 	\