database: renamed functions, "db_" prefix and no CamelCase

Yet another CamelCase removal patch.

src/directory.c

@@ -182,7 +182,7 @@ readDirectoryInfo(FILE * fp, struct directory * directory)
 			if (prefixcmp(buffer, DIRECTORY_BEGIN))
 				FATAL("Error reading db at line: %s\n", buffer);
 			name = &(buffer[strlen(DIRECTORY_BEGIN)]);
-			if ((subdir = getDirectory(name))) {
+			if ((subdir = db_get_directory(name))) {
 				assert(subdir->parent == directory);
 			} else {
 				subdir = newDirectory(name, directory);