Rename host library to libmodpb64-host

This is apparently the convention, and is easy to change before we grow
dependencies.

Bug: 22608897
Change-Id: I22c8b416fae9be49c9cd200f217b5853b8a29758

Android.mk

diff --git a/Android.mk b/Android.mk
index b379e6e..cfe35cb 100644
--- a/Android.mk
+++ b/Android.mk
@@ -23,7 +23,7 @@
 include $(BUILD_STATIC_LIBRARY)
 
 include $(CLEAR_VARS)
-LOCAL_MODULE := libmodpb64_host
+LOCAL_MODULE := libmodpb64-host
 LOCAL_SRC_FILES := modp_b64.cc
 LOCAL_CPP_EXTENSION := .cc
 LOCAL_CFLAGS := -Wall -Werror