Fix comparison of String8 to char* literal

Clang (correctly) interprets

if ("." == sName)

as

if ("." == (const char*)sName)

and recognizes that comparing the pointers isn't what was meant.

With

if (sName == ".")

both clang and gcc see and use String8::operator==(const char *),
ensuring we get the wanted behavior.

Change-Id: Ide240e13214a56f6899f72de3db75dac647e6d4b
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>