[2544] Include stdint.h in the config_parser.h.

Without this header the build fails on CentOS as it does not recognize
uint32_t type.

src/bin/dhcp4/config_parser.h

@@ -14,6 +14,7 @@
 
 #include <exceptions/exceptions.h>
 #include <cc/data.h>
+#include <stdint.h>
 #include <string>
 
 #ifndef DHCP4_CONFIG_PARSER_H