Fix CI on linux

Don't use lldb-mi as the MIDebugger when we're in gdb mode (it's on the
PATH because llvm is installed)

azure-pipelines.yml

@@ -63,7 +63,7 @@ stages:
       env:
         VIMSPECTOR_MIMODE: gdb
         VIMSPECTOR_TEST_STDOUT: true
-        VIMSPECTOR_MI_DEBUGGER: ""
+        VIMSPECTOR_MI_DEBUGGER: gdb
 
     - bash: ./make_package linux $(Build.SourceVersion)
       displayName: 'Package'

run_tests

@@ -23,23 +23,24 @@ fi
 if [ -z "$VIMSPECTOR_MIMODE" ]; then
   if which lldb >/dev/null 2>&1; then
     export VIMSPECTOR_MIMODE=lldb
+
+    if [ -z "${VIMSPECTOR_MI_DEBUGGER}" ]; then
+      if which lldb-mi >/dev/null 2>&1; then
+        export VIMSPECTOR_MI_DEBUGGER=lldb-mi
+      else
+        echo "Couldn't guess VIMSPECTOR_MI_DEBUGGER. Need lldb-mi in path"
+        exit 1
+      fi
+    fi
   elif which gdb >/dev/null 2>&1; then
     export VIMSPECTOR_MIMODE=gdb
+    export VIMSPECTOR_MI_DEBUGGER=gdb
   else
     echo "Couldn't guess VIMSPECTOR_MIMODE. Need lldb or gdb in path"
     exit 1
   fi
 fi
 
-if [ -z "${VIMSPECTOR_MI_DEBUGGER}" ]; then
-  if which lldb-mi >/dev/null 2>&1; then
-    export VIMSPECTOR_MI_DEBUGGER=lldb-mi
-  else
-    echo "Couldn't guess VIMSPECTOR_MI_DEBUGGER. Need lldb-mi in path"
-    exit 1
-  fi
-fi
-
 echo "Testing with:"
 echo " * VIMSPECTOR_MIMODE=$VIMSPECTOR_MIMODE"
 echo " * VIMSPECTOR_MI_DEBUGGER=${VIMSPECTOR_MI_DEBUGGER}"