Workaround unreachable code warning in GrGLCaps

BUG=skia:5833

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3179

Change-Id: I0b5ba57e533280e85b3672f476017dc12aefbbe5
Reviewed-on: https://skia-review.googlesource.com/3179
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 1a7b105..7d1bea3 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -1780,7 +1780,7 @@
     fConfigTable[kIndex_8_GrPixelConfig].fFormats.fExternalType = 0;
     fConfigTable[kIndex_8_GrPixelConfig].fFormatType = kNormalizedFixedPoint_FormatType;
     // Disable this for now, while we investigate https://bug.skia.org/4333
-    if (false) {
+    if ((false)) {
         // Check for 8-bit palette..
         GrGLint numFormats;
         GR_GL_GetIntegerv(gli, GR_GL_NUM_COMPRESSED_TEXTURE_FORMATS, &numFormats);