Fix harmless warning in dwarf_cfi_to_module.cc.

This function already establishes that (signed) i must be positive by the time
it assigns it to (unsigned) reg. Because reg is unsigned, it is impossible for
it to be negative. Because i was already checked for positivity, this check
can be removed entirely. It was not a miswritten check that intended to check
i instead of reg, because i is already checked.

This addresses the following warning:

dwarf_cfi_to_module.cc:135:9: warning: comparison of 0 <= unsigned expression is always true [-Wtautological-compare]

Committed r859
Review URL: http://breakpad.appspot.com/310003

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@861 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/common/dwarf_cfi_to_module.cc

@@ -132,7 +132,7 @@ string DwarfCFIToModule::RegisterName(int i) {
   if (reg == return_address_)
     return ra_name_;
 
-  if (0 <= reg && reg < register_names_.size())
+  if (reg < register_names_.size())
     return register_names_[reg];
 
   reporter_->UnnamedRegister(entry_offset_, reg);