fixes ci script

.appveyor.yml

@@ -31,7 +31,7 @@ install:
 build_script:
   - SET SNAPPY_PATH=C:\projects\%APPVEYOR_PROJECT_SLUG%
   - cd %SNAPPY_PATH%
-  - git submodule update --recursive
+  - git submodule update --init --recursive
   - cd tests\snappycpp
   - dir
   - mkdir build

.travis.yml

@@ -20,7 +20,7 @@ install:
   - env MAKE="make -j2" bash build_nim.sh Nim csources dist/nimble NimBinaries
   - export PATH=$PWD/Nim/bin:$PATH
 
-  - git submodule update --recursive
+  - git submodule update --init --recursive
 
 script:
   - cd tests/snappycpp