Updating to ints from unsigned ints so -1 will be an acceptable value.

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@777 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/client/linux/minidump_writer/linux_dumper.cc

@@ -204,7 +204,7 @@ LinuxDumper::BuildProcPath(char* path, pid_t pid, const char* node) const {
 
 bool
 LinuxDumper::ElfFileIdentifierForMapping(const MappingInfo& mapping,
-                                         unsigned int mapping_id,
+                                         int mapping_id,
                                          uint8_t identifier[sizeof(MDGUID)])
 {
   assert(mapping_id == -1 || mapping_id < mappings_.size());