Travis and test fixes:

- Build server build with latest C/C: Instead of copying the C/C directory
  into server, we now fetch the actual commit or PR into server repository
- Fix travis environment variables (Windows)
- Skip character set tests if the server doesn't support charset/collation
- Don't use CREATE OR REPLACE SQL syntax to make MySQL happy
- Disable TLS connection test for MaxScale
- Don't set TEST environment variables if they are empty

unittest/libmariadb/CMakeLists.txt

@@ -26,6 +26,10 @@ INCLUDE_DIRECTORIES(${CC_SOURCE_DIR}/include
                     ${CC_SOURCE_DIR}/unittest/libmariadb)
 ADD_DEFINITIONS(-DLIBMARIADB)
 
+IF($ENV{TRAVIS})
+  ADD_DEFINITIONS("-DHAVE_TRAVIS=1")
+ENDIF()
+
 SET(API_TESTS "conc336" "bulk1" "performance" "basic-t" "fetch" "charset" "logs" "cursor" "errors" "view" "ps" "ps_bugs" "sp" "result" "connection" "misc" "ps_new" "thread" "features-10_2")
 IF(WITH_DYNCOL)
   SET(API_TESTS ${API_TESTS} "dyncol")