Merge bitcoin#779: travis: Fix argument quoting for ./configure

9e49a9b travis: Fix argument quoting for ./configure (Tim Ruffing)

Pull request description:

ACKs for top commit:
  jonasnick:
    ACK 9e49a9b

Tree-SHA512: 53efa7134de978912d604bc9685bc779f98e2d72e5f77636595676aa420c04fc934a6bb9d560d74b58197943ab86708d3b913e79bc3dfb856681b26dda8724b3

contrib/travis.sh

@@ -3,10 +3,6 @@
 set -e
 set -x
 
-if [ -n "$HOST" ]
-then
-    export USE_HOST="--host=$HOST"
-fi
 if [ "$HOST" = "i686-linux-gnu" ]
 then
     export CC="$CC -m32"
@@ -20,7 +16,8 @@ fi
     --enable-experimental="$EXPERIMENTAL" --enable-endomorphism="$ENDOMORPHISM" \
     --with-field="$FIELD" --with-bignum="$BIGNUM" --with-asm="$ASM" --with-scalar="$SCALAR" \
     --enable-ecmult-static-precomputation="$STATICPRECOMPUTATION" --with-ecmult-gen-precision="$ECMULTGENPRECISION" \
-    --enable-module-ecdh="$ECDH" --enable-module-recovery="$RECOVERY" "$EXTRAFLAGS" "$USE_HOST"
+    --enable-module-ecdh="$ECDH" --enable-module-recovery="$RECOVERY" \
+    --host="$HOST" $EXTRAFLAGS
 
 if [ -n "$BUILD" ]
 then