golang: Update to 1.11.2, fix build errors

When installing a newer host Go, be sure to remove the old host Go. Not
doing so causes errors[1] when trying to build target Go.

[1]: https://github.com/openwrt/packages/pull/7194#issuecomment-435948361

Signed-off-by: Jeffery To <jeffery.to@gmail.com>

lang/golang/golang-version.mk

@@ -11,4 +11,4 @@ endif
 
 
 GO_VERSION_MAJOR_MINOR:=1.11
-GO_VERSION_PATCH:=1
+GO_VERSION_PATCH:=2

lang/golang/golang/Makefile

@@ -18,7 +18,7 @@ GO_SOURCE_URLS:=https://dl.google.com/go/ \
 
 PKG_SOURCE:=go$(PKG_VERSION).src.tar.gz
 PKG_SOURCE_URL:=$(GO_SOURCE_URLS)
-PKG_HASH:=558f8c169ae215e25b81421596e8de7572bd3ba824b79add22fba6e284db1117
+PKG_HASH:=042fba357210816160341f1002440550e952eb12678f7c9e7e9d389437942550
 
 PKG_LICENSE:=BSD-3-Clause
 PKG_LICENSE_FILES:=LICENSE
@@ -180,6 +180,8 @@ endef
 # when go compiles a program, it will use the host std lib
 # so remove it now and force go to rebuild std for target later
 define Host/Install
+	$(call Host/Uninstall)
+
 	$(call GoCompiler/Host/Install/Bin,)
 	$(call GoCompiler/Host/Install/Src,)